依据大量程红外脉冲式激光测距仪测距性能的检测需求，提出了一种基于MODTRAN数据库的激光回波信号模拟的检测方法。在室内环境下模拟激光测距大气回波信号，以实现对测距仪的测距精度及最大测程两项指标的检测。该方法调用MODRAN数据库计算出GJB2241A中仲裁实验的大气辐射透过率，在此基础上建立回波功率的数学模型，并采用FPGA以及模拟延时器件实现预设延时，使得距离模拟与能量模拟自成回路，实现了测距回波的真实模拟。实验结果表明：设计的回波信号模拟系统可实现50 m~22 km的大量程距离模拟，回波延时精度优于2 ns，最大测程的测准率可达90%，满足了激光测距仪性能测试的检测需求。

According to the measuring requirement for the performance measurement of pulse laser range finder with wide range, a new measuring method of laser echo signal simulation based on MODTRAN database was proposed. The laser atmospheric echo signal was simulated by detection system indoor to realize detecting of the two indexes which were the ranging precision detection and maximum range detection of laser range finder better than similar equipments. The MODRAN meteorological parameter database method was adopted to calculate atmospheric radiation transmittance of arbitration experimental in GJB2241A and mathematical model was established on this basis, FPGA and analog delay device were adopted to achieve presupposition time delay, this method made distance simulation and energy simulation becoming a close loop realizing realistic simulation of ranging laser echo signal. Experiments results show that designed laser echo signal simulator system can realize 50 m-22 km wide range distance simulation, echo delay precision is better than 2 ns, measurement accuracy of maximum range is 90% meeting the detecting demand of the ranging performance of laser range finder.