Aiming at problem of node deployment of wireless sensor networks（ WSNs） in areas with obstacle is researched. Node detection models and network coverage rate evaluation method are set up. Based on probabilistic model of sensor

a deployment method is proposed. Random deployment is employed for the obstacle areas. Then quantum genetic algorithm（ QGA） is used to find the optimal node deployment positions. Thus

the target area isomorphism WSNs nodes is efficiently covered is realized. The simulation result that modified QGA effectively improve overall searching ability and convergence speed of algorithm compared with GA and QGA.