Water shortage worldwide is calling for efficient technologies for water purification and reuse. A new process combined pressure assisted osmosis (PAO) and low pressure reverse osmosis (LPRO) was instructed to achieve simultaneous wastewater reuse and seawater desalination. The operating conditions of PAO and LPRO were optimized. Excitation-emission matrix (EEM) spectroscopy and gel permeation chromatography (GPC) were used to investigate the changes of molecular weight distribution (MWD) of organic matters in the hybrid process. Results indicated that water flux was proportional to the pump pressure, and reverse salt flux decreased with the pressure decreasing in single PAO process. Severe permeate flux and salt rejection declination were observed when high concentration NaCl was used as influent in single LPRO process. In hybrid PAO-LPRO process, permeate flux significantly increased compared with single LPRO process and product water had high quality according to the results of EEM spectroscopy and MWD analysis. Salt rejection and removal efficiency of total organic carbon were 97.8% and 98%, respectively. Membrane fouling was moderate and could be removed by simple physical cleaning when secondary sedimentation tank effluent (SSTE) from wastewater treatment plant was used as feed solution and seawater from Hangzhou bay as draw solution.