According to the General Office of the State Council, there are seven public holidays in mainland China: 
1. New Year's Day
2. Spring Festival (Chinese New Year)
3. Qingming Festival
4. Labour Day
5. Dragon Boat Festival
6. Mid-Autumn Festival
7. National Day

It is worth mentioning that holidays in China are often combined with adjacent workdays to form a longer holiday period. In this case, people need to work on weekends before or after the holidays. In Chinese, such a system is called "调休" which means "workday substitution".

The State Council of China has already announced the holiday schedule in 2024. Reference: China's public holidays for 2024

1. New Year's Day

Date: Jan 1
Holiday Length (2024): 3 days
Holiday Period (2024): Dec 30 to Jan 1
Chinese Name: 元旦 (Pinyin: yuán dàn)

New Year's Day is the first holiday of each year on the Gregorian calendar in China. People in China will have three days off when New Year's Day is within or adjacent to a weekend.

2. Spring Festival (Chinese New Year)

2024 Date: Feb 10
Holiday Length (2024): 8 days
Holiday Period (2024): Feb 10 to Feb 17
Chinese Name: 春节 (Pinyin: chūn jié)

The Spring Festival (Chinese New Year) is the most important festival and holiday in China. It does not have a fixed date on the Gregorian calendar as it follows the lunisolar calendar. Usually, the Spring Festival falls between January 21 and February 20. 
The Spring Festival holiday always starts on Chinese New Year's Eve and lasts seven days or more (various in different companies).

3. Qingming Festival (Tomb-Sweeping Day)

2024 Date: Apr 4
Holiday Length (2024): 3 days
Holiday Period (2024): Apr 4 to Apr 6
Chinese Name: 清明节 (Pinyin: qīng míng jié)

The Qingming Festival (Tomb-Sweeping Day) is a traditional Chinese festival for peaple to visit the tombs of their ancestors. During the day, people clean the ancestral gravesites and make ritual offerings to their ancestors.
As a traditional Chinese festival, the Qingming Festival follows the lunisolar calendar and does not have a fixed date on the Gregorian calendar. Generally, the date falls on April 4, April 5, or April 6. 

4. Labour Day

Date: May 1
Holiday Length (2024): 5 days
Holiday Period (2024): May 1 to May 5
Chinese Name: 劳动节 (Pinyin: láo dòng jié)

In China, Labor Day is May 1, the same as International Workers' Day. It is statutorily a 1-day public holiday, but in practice, the holiday length can be 3 or 5 days by workday substitution. 

5. Dragon Boat Festival

2024 Date: Jun 10
Holiday Length (2024): 3 days
Holiday Period (2024): Jun 8 to Jun 10
Chinese Name: 端午节 (Pinyin: duān wǔ jié)

The Dragon Boat Festival is a traditional Chinese festival that originated from the worship of natural celestial phenomena and evolved from dragon worship in ancient times. Also, it is a commemoration of the ancient poet Qu Yuan.
As a traditional Chinese festival, the Dragon Boat Festival follows the lunisolar calendar and does not have a fixed date on the Gregorian calendar. Usually, the date falls on late May or June.

6. Mid-Autumn Festival

2024 Date: Sep 17
Holiday Length (2024): 3 days
Holiday Period (2024): Sep 15 to Spe 17
Chinese Name: 中秋节 (Pinyin: zhōng qiū jié)

The Mid-Autumn Festival is a traditional festival celebrating the harvest in Chinese culture. It is also also known as the Moon Festival or the Mooncake Festival. 
Like other traditional Chinese festivals, the Mid-Autumn Festival follows the lunisolar calendar and does not have a fixed date on the Gregorian calendar. Usually, it falls between mid-September and early October. When the date falls on the end of September (Sep 29 or Sep 30), it will be combined with the National Day and create an 8-day holiday.

7. National Day

Date: Oct 1
Holiday Length: 7 days
Holiday Period (2024): Oct 1 to Oct 7
Chinese Name: 国庆节 (Pinyin: guó qìng jié)

National Day, officially the National Day of the People's Republic of China, is the last public holiday of the year in China. It is a holiday to commemorate the establishment of the People's Republic of China on October 1, 1949. People also call the National Day holiday "Golden Week" because the 7-day holiday brings numerous business opportunities.