Based on polarization characteristics of non-spherical particles, a short-range lidar system for real-time standoff detection of bioaerosols was developed. The system includes two laser sources and depolarization components. Linear polarization purity of the laser beam is 1/500. The polarization and elastic scattering signals are collected by a Cassegrainian telescope. In a semi-closed bioaerosol chamber, 10 kinds of bioaerosol were mixed and interrogated by 355, 532, 1064 nm laser beam sequently. Linear polarization measurements were performed. The results showed that the depolarization ratios are wavelength-dependent, and the identification of bioaerosols can be achieved through the application of Euclidian correlation degree and Mhalanobis distance.