To meet the development requirements of high-precision spread-spectrum telemetry track and command (TT&C) equipment, the high-precision simulation technology of direct sequence spread spectrum (DSSS) signal is studied and the simulation technology of carrier phase is proposed based on online correction technology and linear interpolation, which avoids the simulation of improving phase precision by sacrificing resources and can simulate relative motion between a receiver and an object. The effectiveness of this algorithm has been corroborated with theoretical analysis, simulation and measured data and has been applied to certain spaceflight simulator successfully.