Q: If my stay in China exceeds 30 days, can I apply for an extension?

A: Foreign nationals planning to stay in China for over 30 days shall apply in advance for visas corresponding to their purposes of stay at Chinese embassies or consulates.

If you have to stay longer than 30 days for appropriate and sufficient reasons after entering China without a visa, you shall apply for stay permits at the exit and entry administrations of public security authorities of China.