The ability of a detection system to recognize detection targets determines whether or not the functional modules connected to the laser detection system can work normally. A pulse width-intensity modulation scheme is proposed to simulate crossing target echo signals at high speed in the laboratory. This scheme can change the peak value of the output light pulse by controlling the pulse width of an input pulse signal and simulate the peak value changes of echo signals. In addition, the circuit implementation is designed to drive an 860 nm semiconductor laser for testing. The test results reveal that the input pulse signal with a pulse width of 8-16 ns corresponds to the output pulse signal with the peak power of 3.7-8.3 W. Taking the pulse width-intensity modulation module as the basic physical realization unit, we present a high-order simulation scheme of echo signals to simulate more information of target echo signals. This modulation method is simple in the principle, easy in circuit implementation, and low in costs, which provides a new direction for the design and inspection of the target recognition function of a laser detection system.