Validity of a visa refers to the period within which the visa holder is allowed to enter China (right up to midnight Beijing Time on the final day of validity). 

The number of entries refers to the number of times the visa holder is permitted to enter China within the visa’s period of validity. 

Duration of stay refers to the longest period the visa holder is allowed to stay in China on each visit, and this is counted from the day following entry into China.
 
When all the permitted entries are used up, the visa is no longer valid. Even if there are still unused entries, the visa is no longer valid if the period of validity has already expired. In either case, the visa holder should apply for a new visa if another visit to China is planned.
The holder of a visa is eligible to enter China at any time prior to the expiry of its validity (allowed to enter China before midnight Beijing Time on the last date of its validity) provided that permitted entries on the visa have not been used up. The holder’s planned duration of stay in China must not exceed the duration stated in the visa.