The invention provides a method and system for detecting object micro Doppler characteristics by use of double pulses. Through coherent and conjugation correlation processing on local oscillator signals and echo signals for multiple times, errors caused by laser signal frequency and phase jittering are eliminated, the influence exerted by the radial speed of an object on micro Doppler measurement is also eliminated, the measurement accuracy for a phase difference caused by object micro motion is improved, at the same time, the difficulty in extracting micro Doppler information is reduced, signal processing is carried out completely within a time domain, frequency domain conversion is canceled, and the operation amount is greatly decreased. The invention also provides a system for realizing object micro Doppler characteristics by use of double-pulse laser signals. Beam splitting is carried out on laser signals by use of a beam splitter mirror, a photoelectric detector is utilized for coherent processing on the laser signals, and a DSP module is employed for conjugation correlation processing. Through combination of simple devices, high-precision object micro Doppler characteristics are measured, and the system has the advantages of simple structure and easy realization.