Abstract: For the single base station CORS RTK has low measurement accuracy in surface deformation monitoring of mining subsidence, an adaptive Kalman filter algorithm based on variance estimation principle is constructed. Correspondence CORS RTK is used to collect the plane coordinates and normal height of each epoch. Based on the actual CORS RTK measured data and comparative analysis results of the fourth-class level measurement, the CORS RTK measurement accuracy after filtering has been greatly improved, which meets the accuracy requirements for surface movement deformation monitoring of mining subsidence.