A theory validation system of coherent lidar with balanced coherent detection and chirped amplitude modulation is built based on narrow line width diode laser,acousto-optic frequency shifter,Mach-Zehnder intensity modulator,and all-fiber coherent detection optics.The principle of the chirped amplitude modulation coherent lidar is introduced.The design of direct digital synthesis(DDS) based chirp signal generation and radio frequency signal processing circuits are also discussed.The measurement of time resolution and minimum detection power of the system is conducted and some phenomena in the experiment are analyzed.