Passengers shall accept the security check according to the relevant regulations before entering the subway stations. Security inspectors have the right to stop any person from entering the station if he or she refuses to undergo the security check.

Passengers are not allowed to take items prohibited by relevant laws and regulations into stations. Security inspectors have the right to handle cases of carrying prohibited items according to relevant regulations and shall make timely reports to public security organs for further handling according to corresponding laws. 

Items carried by passengers shall be no more than 30 kg in weight, 1.8 m in length, or 0.5 m in width or height. Passengers are not allowed to take electronic conveyances or other items, other than barrier-free electric wheelchairs, that may disturb the normal passage in stations or trains, or affect safe operation. 

Children below 1.3 m shall be accompanied by at least one adult. The accompanying adult(s) shall take care of the children during the whole process to ensure the children's safety. 

People may not be allowed to enter the subway stations or trains if they are improperly dressed or intoxicated with risks of provoking violence. Those behaving in other bad manners or, if possible, endangering the health and safety of other passengers due to their diseases or health conditions are also prohibited from entry. People with reduced mobility or mental disorders shall be accompanied by their guardians or other healthy adults when taking the subway. 

(Source: Official website of Beijing Subway)