Abstract: Abstract：Aiming at the problems such as the concealed faults and difficult monitoring of diverting pulley assemblies in traction elevators, as well as the slow software response and single function of existing monitoring systems, this paper develops the software of a diverting pulley assembly monitoring system based on STM32 single-chip microcomputer. The system realizes full-process automation including data acquisition, processing, analysis, display and early warning. Adopting a modular design concept, the software consists of main control program, ADC acquisition program, serial communication program, display and early warning program, and fault diagnosis program. The monitoring accuracy and response speed are improved by optimizing the data processing algorithm. Meanwhile, a user-friendly human-machine interaction interface is designed to facilitate operation and maintenance for staff. Verified by software debugging, joint tests and field application, the software can accurately process data collected by sensors, and realize real-time early warning and fault location for abnormal conditions of diverting pulley assemblies with a response time within 3 seconds. Working in coordination with the hardware system, it meets the practical requirements for safety monitoring of elevator diverting pulley assemblies, and possesses high practicability and popularization value.