To address the driving safety issues caused by abnormal tire pressure in vehicles, this paper designs a tire pressure monitoring and alarm system based on GSM SMS. The system uses an STC89C52 single-chip microcontroller as the controller, and designs the tire pressure acquisition circuit, LCD display circuit, buzzer circuit, LED light circuit, and GSM SMS sending module circuit. The monitoring effect of the system is simulated and verified by circuit simulation software, and the circuit system is fabricated and tested. Results show that the designed tire pressure monitoring and alarm system can realize tire pressure monitoring. When the tire pressure is within the standard range of 220 kPa to 240 kPa, the relative error of the actual measurement results does not exceed the threshold of 4%. Moreover, when the tire pressure is abnormal, it can promptly achieve on-site alarm through the buzzer and LED lights, and remote alarm through the GSM module, thus achieving the expected effect and having strong application value.