Abstract: A disk brake monitoring system of mine hoist to real-timely monitor three parameters of brake clearance, braking force and idle motion time was designed based on the three parameters can reflect braking performance of disk brake of mine hoist. The system uses two micro-processers, one is used to measure brake clearance and finish functions transform, the other is used to measure idle motion time and braking force. And it uses fault diagnosis technology based on expert system to judge abnormal states of disk brake running. The actual application showed that the system has high measuring precision, good real-time performance and high reliability.