>Since 1990s,the satellite altimeter made a great contribution to the monitoring of sea level changes, ocean circulation,regional sea surface topography,climate change et.al.However,satellite altimeter has bias or drift when measuring the Sea Surface Height(SSH),so it needed to be calibrated.The principle of calibration is to measure the sea surface height in the same position of satellite when it travel through, then compare the in-situ SSH with the value of altimeter measurements,and achieve the bias or drift of the altimeter.In this paper,a self-designed GPS buoys was used to measure the SSH when the satellite transit above.Four experiments was done to calibrate HY-2altimeter in Shidao town of Shandong province and Qinglan town of Hainan province.The results showed that:①In support of GPS reference station,the precision of GPS buoy in measuring the SSH was better than 50mm.This could satisfy the demand of altimeter calibration.②There was a systematic bias in HY-2satellite altimeter measurements.③By using the data of relative calibration between Jason-2and HY-2altimeter and absolute calibration results,HY-2altimeter can reach the international advanced level.