Abstract: A cycle-slip detection and correction algorithm suitable for real-time precise point positioning(PPP) was proposed.There are three main steps in the algorithm: ① Possible cycle-slip affected satellites and cycle-slip free satellites were determined using M-W and ionosphere residual observation combination;② Cycle slip detection and correction was conducted for possible cycle-slip affected satellites using cycle-slip free satellites information and observations of current epoch and previous one or several epoch(s),based on the new developed epoch-differenced cycle slip detection model;③ Refinement process for cycle slip detection failed satellites to try to repair cycle slip.The experimental results show that the new algorithm can detect and repair cycle slip correctly and efficiently in real time PPP.