Abstract Aiming at the problems of low positioning accuracy and poor reliability in areas without CORS services, we propose a method for differential positioning using a self-established base station with smartphone. The method uses an external antenna to improve the quality of GNSS observation data and uses devices such as RF shielding boxes to set up a self-established base station. The Huawei Mate40 smartphone is used as a mobile station, and RTK positioning is performed with both traditional CORS base station and self-established base station. Static, walking, and cycling experiments are designed to evaluate the service capability of self-established base station. The experimental results show that in the static experiment, the RTK positioning accuracy of Huawei Mate40 smartphone with self-established base station can reach centimeter-level accuracy. In the dynamic experiment, the RTK positioning accuracy of Huawei Mate40 smartphone with both self-established base station and CORS reference station can reach decimeter-level accuracy, with a difference in planar positioning accuracy of about 0.1 m between the two methods. The self-established base station based on a smartphone can provide stable reference station services and meet the needs of surveying and mapping work in specific scenarios.