Abstract: To ensure accurate thrust measurement of hydrogen oxygen rocket engines under high altitude environment，according to the characteristics of high altitude simulation test on hydrogen oxygen rocket engine, the theory of thrust measurement and the actual layout requirements，the thrust measurement device design of cryogenic and vacuum environment was researched. The spring design technology of small elastic resistance was developed. A control technology to keep the calibration force and the thrust axis consistency was realized. The implementation technology on moving to static of the calibration mechanism for the seal about the vacuum cabin，and the control technology of pipeline constraint for thrust measurement influence were solved. A set of thrust measurement device was successful developed，and the application of a model of rocket engine test has achieved good results.

Key words: Rocket engine, High altitude simulationt, Thrust measurement