Laser reconnaissance and warning radiation lab simulation test mode in laser extinctive chamber is analyzed. A simulation test project using laser designating simulator is p roposed. The jammingmode reasons and exp ressions of false alarm caused by laser diffuse reflection in extinctive chamber are analyzed. According to the theoretical analysis of laser designator and rangefinder used in battlefield and atmospheric propagation, simulation calculating model ofwarning laser signal’s energy and power is given. The influences on laser reconnaissance and warning radiation simulation test, which include diffuse reflection characteristics and diffuse reflection ratio of some different surface and other factors are discussed. Some theory basis and reference about laser passive reconnaissance and warning radiation simulation test are also offered.