Abstract: The fixed range fuse needs to complete a rapid height determination in the flight descent segment of the projectile, and then control the projectiles action precisely. Comparing different height determination methods, this article puts forward a compound height measurement method using pulsed laser and gravity acceleration sensor, and calculates the measurement precision by deep analysis in measurement error. The prototype test on inclined platform shows that the maximum angle error is less than 0.3 under static condition; 0~500 m height determination experiments show that the maximum error between the average measured value and the actual value is 2.5 m, which has no correlation with the target distance.