Along with the wide popularization and application of BeiDou navigation system, the problem of its system integrity gradually come to our vision, how to ensure the integrity of BeiDou satellite is becoming the problem that the BeiDou system needs to solve urgently. In this paper, based on the integrity detection of satellite navigation system, the North bucket system as the research object and platform, the RAIM monitoring algorithm for the weighted least squares of the BeiDou navigation system receiver is designed, and the accuracy of the software algorithm is proved by using the existing intact detection equipment to collect the data to verify the algorithm.