This paper discusses the definition of the public space in the elevator car under the framework of the Constitution,as well as the violation of the personal information and privacy of passengers by the camera in the elevator.This paper analyzes the shortcomings of the legal reservation methods adopted by the Constitution for citizens'freedom of communication and communication secrets,combs out the new forms of infringement of elevator passengers'privacy under the background of the Internet of Things,and puts forward some suggestions for improving the mechanism,such as including Internet of Things service providers into the main body of infringement of communication secrets,strengthening the implementation of the personal information protection law,and strengthening the coordination between laws and technical regulations.