Nowadays, lots of studies show the potential value of laser echo intensity in three-dimensional reconstruction of laser detection system. However, raw intensity information could not be used without correcting, since target geometry could also influence laser echo greatly. Target angle that is the angle between laser axis and target normal is important geometry information in intensity correcting. This paper studies the method to calculate target angle, which, as a result, could have great benefits in laser intensity correcting and further in three-dimensional reconstruction. The target angle could be calculated from the mathematical model between the target angle, distance and pulse width based on the laser space translation model presented. Simulation and experimental results show that, the method proposed can calculate the target angle effectively, which have great contribution in laser intensity correction and further in three-dimensional reconstruction.