Ms. selene, Singapore passport holders are exempt from a visa to Mainland for 15 days at most, if you want to travel in China for more than 15 days, you'd better apply for a Chinese tourist visa in advance, it is easy to get a China visa in Singapore for Singapore passport holders, however, if you want to extend you stay in China after 15 days visa free time, you can go to the local Exit & Enter department to apply for a Chinese visa which will permit you stay in China for generally 30 days. In this way, it is a little complex, you must go to the places which have the exit & enter department.