The invention discloses a high-speed narrow pulse current amplifier based on the CMOS technology, and the amplifier comprises a current input amplifier stage, an automatic biasing current source load, a first stage automatic biasing voltage amplifier, a second stage automatic biasing amplifier, and a shaping circuit. The current input amplifier stage improves the output impedance through the automatic biasing current source load, and converts a current outputted by an APD detector unit into a voltage signal. The voltage signal is amplified by the first stage automatic biasing voltage amplifier and the second stage automatic biasing amplifier, and then is shaped by the shaping circuit, thereby enabling the output voltage STOP to reach a digital pulse. A power supply VCC is used for supplying power to the current input amplifier stage after being filtered by a low-pass filtering circuit. The current amplifier provided by the invention can be set in a large-array laser radar pixel unit, is used for the preposed current amplification, can increase the output impedance of the input amplifier stage, and improves the voltage gain of a small signal. Meanwhile, the amplifier does not need an additional biasing circuit, reduces the power consumption, and reduces the area of the pixel unit.