Abstract: For earth observation satellites with sun-synchronous, circular orbit and three-axis stabilization attitude, we have studied the wireless link characteristic of data transmission and coverage performance of antenna using J2 orbit model and coordinate transformation. The results show that on the elevation plane the antenna beam should be earth-matched to compensate the space loss and maintain the uniformity of received level of ground station. On the conical surface of the maximum angle, the distribution of actual antenna beam pointing is not uniform. The distribution of beam pointing ,when the satellite is entering or leaving the earth station's tracking range, is maximum along the flight direction of the satellite, and minimum in the direction perpendicular to the flight direction. So, combination of optimal beam design based on coverage statistics with proper antennas arrangement on-board, better coverage and higher quality of data link could be achieved.