The invention discloses a pulse laser range finding system echo signal processing device and method. The device comprises a main controller, a driving circuit, a laser, an optical system, a PIN photoelectric detector, a main wave amplifier, a fixed threshold time discrimination circuit, an APD photoelectric detector, a preamplifier, a main amplifier, an autocorrelation detection circuit, a dual-threshold time discrimination circuit, a high voltage bias circuit, a first peak sampling circuit, a first A / D conversion circuit, a second peak sampling circuit, a second A / D conversion circuit, a D / A conversion circuit, an LED display screen, and an upper computer. The first peak sampling circuit, the first A / D conversion circuit, the second peak sampling circuit, the second A / D conversion circuit, and the D / A conversion circuit are combined with the dual threshold time discrimination circuit to stabilize an echo signal amplitude. At the same time, the autocorrelation detection circuit is used to extract an echo signal from a noise, a system signal-to-noise ratio is increased, range finding accuracy is improved, and a system measurement range enlarged. And by using the method, a system integration degree can be increased.