um-wave length, fiber-based micro pulse lidar of profiling atmospheric CO 2 was designed, The performance of this lidar was simulated. The transmitter of micro pulse lidar is based on semiconductor laser plus erbium-doped fiber amplifier with a saturated output power of 37dBm. The receiver employs photon counter and near infrared photomultiplier tube with quantum efficiency of 1%. A polarization-independent fiber-optic circulator is used as the transmit-receive switch. The system utilizes fiber devices for almost all components, e.g. wavelength-division-multiplexers/demultiplexers, isolator,filter,coupler, which make the system robust. Characteristic of this lidar is micro pulse energy 20uJ, high repetition rate of 20kHz and miniaturization. Signal simulations indicate that signal-to-noise ratio below 4.7km is more than 10∶1(18×106 pulse).Anode dark count of 2×105 /s limits the system performance. New InGaAs/Si APD with separate absorption and multiplication region will improve the lidar performance.