A method of user proportion investigation and population estimation in a region for mobile communication operators, including the following steps: S1. completing a WiFi network construction in the region; S2. a mobile phone user in the region sending a verification code request for WiFi login to a background by using a client; S3. the background receiving the request from the user, and recording a mobile phone number and a request time of the user; S4. the background completing an identification and classification processing of the operator of the mobile phone number, and obtaining the user proportion in the region for the communication operators within a set period of time; and S5. calculating a population amount in the region according to a number of mobile phone signaling provided by one mobile communication operator thereof and the user proportion in the region for the corresponding communication operator obtained in S4.