According to China's existing laws, how can citizens view the video of surveillance cameras? What kind of application do you want? According to what laws and regulations?

There is no regulation, go directly to the public security bureau to apply, the police beat people, the inspector team will investigate and deal with them, and will give you the result. If it is deleted automatically by the system because the time is up, there is no way out. Who told you not to check in time? If it is artificially deleted because the time is not up, you can complain to the inspector brigade or the local discipline inspection commission.