The invention discloses a method for calibrating GPS standard time in a TD-SCDMA wireless communication system, which comprises the following steps: firstly, obtaining base station GPS standard time by a mobile terminal which needs positioning, then, obtaining signal round trip time from a base station by a wireless network controller, obtaining receiving and sending time differences from the mobile terminal, calculating signal transmission delay according the time differences, then, sending the signal transmission delay to a corresponding mobile terminal by the wireless network controller, and calculating terminal GPS standard time according to the GPS standard time and the signal transmission delay of the base station by the mobile terminal. More accurate GPS standard time can be obtained on the mobile terminal through transferring measured base station signal transmission delay and calibrating base station side GPS standard time which is obtained by the mobile terminal, thereby the receiving sensibility of an A-GPS receiver in a terminal device can be effectively improved, and the first positioning time can be reduced.