The invention discloses a method of using an intelligent mobile phone to assist indoor positioning. The accuracy of indoor positioning is improved through accurately positioning the floor of a user. The method comprises steps: an air pressure change trajectory when the user moves in a building is monitored through an air pressure sensor of the mobile phone; when multiple users are in the same elevator or Wi-Fi reading of the multiple users is close, the air pressure sensors of the users are calibrated in pairs; the air pressure change trajectories of the users are all uploaded to a center server, the server combines the multiple trajectories, a trajectory map containing the air pressure value of each floor is obtained, and thus, according to the air pressure reading of the user, the floor of the user is positioned; and according to Wi-Fi signals around the user with the known floor, a Wi-Fi map corresponding to the floor is built, and the Wi-Fi map is used for positioning a floor for a user whose mobile phone is not provided with the air pressure sensor. the method can position the floor of the user in the current building, the indoor positioning range can be narrowed, and the positioning precision is improved.