The invention relates to an automobile anti-collision alarm 
system based on pulse 
laser ranging, which belongs to the technical field of 
electronics, which is provided with a 
control circuit, a 
laser transmitting circuit, a 
laser receiving 
amplifier circuit and relevant circuits. A 
single chip microcomputer STC12C5A60S2 is the core of the 
control circuit, after laser pulse signals are in 
spectral processing by a spectroscope with the support of corresponding programs, one channel of the laser pulse signals is reflected by a reflector to be directly received by a PIN receiving circuit, another channel of the pulse laser signals is reflected by an automobile ahead, and then is received by the APD (avalanche photo 
diode) laser receiving circuit, after receiving time of each of the channels of the laser pulse signals is accurately corrected by a 
discriminator circuit, the channels of the laser pulse signals are transmitted to the 
single chip microcomputer master 
control circuit to be processed, the distance from an automobile with the automobile anti-collision alarm 
system and the automobile ahead is monitored in real time, and the 
system can give a sound and light alarm when the automobile is in danger, simultaneously reminds a driver of controlling automobile speed in a voice manner and keeping the distance from the automobile to the automobile ahead. In addition, when necessary, the system outputs 
brake signals to control the automobile to 
brake. Besides, the automobile anti-collision alarm system is large in measurement range, high in 
directivity, 
interference resistance, precision and practicality, fast in 
response time and simple in structure, and has high economic benefit and social benefit.