Abstract: Based on two independent physical phenomena:laser induced fluorescence(LIF) and depolarization resulting from elastic scattering on non-spherical particles, a short range lidar system for real-time standoff detection of bio-agents was developed. The lidar system included three laser sources, two receiving telescopes, one depolarization component and fluorescence spectral signature analyzing spectrograph. It was designed to provide the stand-off detection capability at ranges from 200 m up to several kilometers. For fluorescence excitation, 3rd (355 nm) and 4th (266 nm) harmonics of Nd:YAG pulsed lasers were used. They emitted short (about 6 ns) pulses with the repetition frequency of 20 Hz. Collecting optical system for fluorescence echo detection and spectral content analysis included 25.0 mm diameter f/4 Newton telescope, Czerny Turner spectrograph and a 32-channel PMT. The depolarization and Mie echo signal were collected by a Cassegrain telescope with an aperture diameter of 12.5 mm. Through the simulative calculation of SNR of fluorescence measurement, it was found that, with the minimum detectable SNR value of 10 as reference, the bio-agent cloud with concentration of 10 000ACPLA at the distance of 1 km could not be detected in daytime, while a rather good signal intensity could be obtained in nighttime. The preliminary analysis to the depolarization measurement results indicated that:(1) the depolarization ratios were wavelength-dependent; (2) depolarization measurement using multiple wavelengths could increase discrimination efficiency significantly.