In order to improve the accuracy of r otor unsteady load calculation, a viscous vortex particle method (VVPM) based w ake simulation is integrated into the rotor comprehensive analysis (CA) module, then a new coupled method is established. In this model, the first principle bas ed VVPM is capable of simulating the wake distortion and diffusion without any e mpirical parameter, while the rotor CA is able to calculate the elastic deformat ion and unsteady loads of rotor blade effectively. And through the loose couplin g strategy, the information can be efficiently exchanged between two modules. Ba sed on the developed method, the SA349/2 helicopter is chosen to be tested, and two traditional flight regimes are investigated thoroughly. The result shows tha t the VVPM/CA coupled analysis can predict the w ake geometry and unsteady loads accurately.