Based on a monolithic transceiver chip, a lens-assisted beam scanning lidar system is built. The monolithic transceiver chip is fabricated based on silicon-based integration technology, which integrates a 1×4 optical switch and 2×2 transceiver array. The transceiver consists of a grating transmitter in the middle and a surrounding U-shaped photodetector. The experimental results show that the response time of optical switch is about 5.4 μs, and the photocurrent response of the transceiver is 0.3 A/W. Combined with our self-developed scanning electronic control device with the response time of 300 ns, a frequency modulated continuous wave lidar system is realized, and the ranging experiment is carried out in the range of 1 m.