In order to realize some ammunition exploding at preconcerted height to achieve the optimal destructive effects, a kind of height and angle finding system was put forward based on laser multi-detecting module. This system could calculate the flying height, pitch angle and roll angle of missile with use of the un-coplanar narrow view field laser module measuring the distance between ground and missile. Multi-variable Taylor formula was applied to analyze the height-finding and angle-measurement error induced by the range-finding error. The analysis results indicate that the error meets the required standard for some air-to-surface ammunition.