Vehicle sideslip angle is employed by the vehicle stability control system (VSC) as the basis for predicting the vehicle maneuverability and stability. The scheme of sideslip angle test system based on the ‘1+2’ GPS technology, i.e. one base station and two roving stations, was proposed, and the corresponding system was developed. The paper firstly introduced the primary sensor matching and the devices installation, then described the computation method for the sideslip angle based on the GPS data. Finally, the systematical road way tests were conducted, and the effectiveness of GPS scheme was verified by the same group test data of sideslip angle obtained from the double-direction optical speed sensor. The sideslip angle test system was characterized of high frequency and accuracy for positioning, velocity and sideslip angle measurement for vehicle body and road wheels, and of convenient installation on the spot. It can provide the credible test ways for the verification of the sideslip angle estimation algorithm and the control logic of VSC. 