Adaptive QOS routing algorithm (DAQR) based on discrete particle swarm algorithm for wireless sensor networks is proposed to solve the problem that the existing QOS routing algorithms can't take count into both adaptive ability and network energy consumption in room environment. In the work, different QOS parameters are defined as different optimization objects on the research basis of AIRE and WAIER. The QOS routing setup process is abstracted to multi-objective optimization process. It works out multi-objective optimization strategy about routing based on classic particle swarm algorithm, genetic algorithm and niche algorithm. Simulation results prove that DAQR can effectively adapt to the change of environment, and show better expandability when network scale expands.