The markets of Shanghai and Shenzhen, the most important markets in China, are open from 9:30 to 15:00. The Hong Kong market is open from 9:30 to 16:00.
The time difference between China and Barcelona is 6 hours in summer and 7 in winter, so to know the local time you have to subtract. For example, Shanghai closes at 8:00 in summer, European time.