A laser short-range dynamic scan detection method is proposed based on the optical-multiplexing mechanism. Based on the heavy-tail function, a mathematical model of pulsed laser emission waveforms is established, and the shock responses and the echo equation in the pulsed laser short-range dynamic detection are deduced. A statistical probability distribution model of the pulsed laser ranging is established, and the influence mechanisms of the pulsed laser emission power, pulse width, threshold detection voltage, equivalent root-mean-square (RMS) noise voltage, and the laser exit angle on the probability distribution of the ranging are studied. The results show that, the ranging precision increases and the distribution curve gradually deviates from its true value with the increase of the laser emission power. The ranging precision decreases progressively as the laser emission pulse width increases. As the threshold voltage increases, the distribution curve shifts to the right. As for the distance measurement distribution curve, its width increases and its amplitude decreases with the increase of the equivalent RMS noise voltage. The ranging distribution curve shifts to the right and the ranging precision decreases as the laser exit angle increases.