Is there a checkpoint in China only in Beijing?

No. A checkpoint is an institution that checks people who enter a specific area, their vehicles and their belongings. Beijing is not the only place in China where checkpoints are set up. Beijing, referred to as "Beijing", is the capital of People's Republic of China (PRC). One of the four municipalities directly under the Central Government and the second largest city in China. It is a national political center, cultural center, international exchange center and scientific and technological innovation center.