Firstly four-year altimeter data from Topex/Poseidon satellite and one-year altimeter data from ERS-1 satellite in the China sea and its vicinity (0°-40°N,105°- 135°E) are pre-processed to eliminate the gross error in the altimeter data. Then they are used to determine the mean sea surface with the stacking method along the satellite repeated collinear tracks. After the contributions of sea surface topography are reduced from the mean sea surface, the 30' × 30' geoid undulations are obtained. Afterwords the 30' × 30' gravity anomalies are recovered by using the inverse Stokes formula with fast Fourier transform technique and the least squares collocation respectively. The precision of the geoid undulations and the gravity anomolies in the research area are 8.5cm(RMS) and 3.5 × 10-5m / s2 (RMS) respectively.