The embodiment of the invention discloses a file transmission detection method and a related device, so as to prevent a file with a hidden safety danger from accessing and operating device data. The method of the embodiment comprises steps: a first mobile terminal receives a connection request sent by a second mobile terminal; the first mobile terminal builds temporary user space according to the connection request; the first mobile terminal builds connection with a second mobile terminal through the temporary user space; the first mobile terminal receives a sharing file sent by the second mobile terminal through the temporary user space, and the sharing file is saved in the temporary user space; the first mobile terminal judges whether the target file received by the temporary user space is safe; and the first mobile terminal processes the target file according to a judgment result. The embodiment of the invention also discloses a mobile terminal. Due to the embodiment of the invention, the file with a hidden safety danger can be prevented from accessing and operating device data.