A dual-wavelength lidar with 532nm and 589nm was setup inWuhan Institute of Physics and Mathematics (30.5°N, 114.3°E) to detect atmosphere from 1～110km simultaneously. Recently, a pulse dye laser (ND6000) pumped by the 532 nm beam was employed to transmit a 770 nm laser beam, which allow the new dual-wavelength lidar to measure the potassium layer and sodium layer simultaneously. In this paper, the dual-wavelength lidar systems and resonant fluorescence data processing method are introduced. The number density and column density of the sodium layer and potassium layer over Wuhan were calculated also. The results show that the density and column density of sodium layer and potassium layer both are almost the same with previous results observed by other sodium and potassium lidar in Mid-latitude region. Moreover, another interesting thing found is that potassium and sodium layer are not always the same.