This work aimed to design an observational network of the air-sea boundary layer over the Bohai and the Yellow Sea, China, and further investigate the effects of these observations on a U.S. numerical prediction model (Weather Research and Forecasting model, WRF). Statistical analysis of the regional characteristics of the air-sea elements, model error, and observation system simulation experiments (OSSE) were conducted. Evaluations of the observation network were conducted under different wind and weather conditions and the advantages and disadvantages of each configuration scheme were weighed. The 6-h NCEP/NCAR FNL (NCEP Final Operational Global) reanalysis data, NCEP real-time global daily sea surface temperature (RTG_SST) analysis data, and buoy and oil-platform observational data were used. Results showed that the forecast humidity and wind were greatly affected by the actual direction and velocity of the wind, and humidity was better predicted under easterly and northerly wind conditions. Moreover, in the moderate southerly wind case, the forecast winds were closer to the observations. It was found that the forecast accuracy of temperature could be significantly improved by configuring the station network based on regional characteristics. Based on a comprehensive overview of the model simulations, suggestions for configuring the air-sea observation stations so as to improve numerical forecast accuracy are provided.