We demonstrate a monolithic transceiver based on a CMOS-compatible silicon photonic platform for lens-assisted beam-steering (LABS) light detecting and ranging (Lidar) application. By implementing an on-chip two-dimensional transceiver array and off-chip lens, beam emitting, steering, and receiving are realized simultaneously on a single chip. The transceiver is designed with a structure of a U-shaped vertical Ge photodetector surrounding a grating for high-efficiency light transmission and reception. The on-chip photodetector has a bandwidth of 87 MHz, a responsivity of 0.3A/W, and a detection sensitivity of -20dBm. For proof-of-concept demonstration, a time-of-flight Lidar system is achieved for target ranging with a detection distance of 5.2 m, a scanning angle of 2.86°, and a scanning speed of 5.3µs . This work demonstrates a feasible solution to integrated Lidar with beam emitting and receiving on one single chip based on LABS.