Chirp signal technique is one of the key techniques for measuring sea surface altitude.Using altimeter aboard satellite to determine the altitude of sea level have been adopted at abroad.In the late 1980s,we had begun with learning technical skills through trail and error.Up to 1990 we had carried on a airflight by altimeters aboard a plan and achieved datao f sea level and wave altitude with wave altitude resolution in 0.75m.This technique experiment is newly establish in China.