Coverage problem is one of the hot issues in the research of wireless sensor networks（ WSNs）

that is in a specific region

while regarding sensor position as center of circle

which form detection region

whether can cover the detected area or not. Aiming at above problems

put forward a distributed WSNs coverage blind spot discovery algorithm based on polar coordinate

the algorithm uses polar coordinate to express relationship between nodes

through geometric algorithm to detect whether there is blind spot of coverage in WSNs. Simulation results show that

the algorithm can effectively detect coverage blind spot and all boundary node

and detection efficiency is enhanced.