I have been issued a single entry work visa for china ( Z ) How many days can I stay in china

Z visa holders need to apply for a residence permit from a local county level Public Security Bureau within 30 days after entering China. It is a general request sir. Then, the residence permit works as multiple entries. You can not stay for 90 days and if so, you overstayed your visa in China. Now, you'd better go to the nearest police station. And they will help you.

But if you follow the step to apply for a residence permit within 30 days, but it has not done yet, it may be another case since you have paper or receipt showing that your residence permit is under processing.