Based on coastal high-resolution (2′×2′) coupled wave-tide-surge interaction numerical model, the effects of radiation stress on wave heights and sea level in the coastal area of Huanghe Delta were studied. By comparisons of simulated and measured wave heights and sea level for two mediately strong weather cases, it is demonstrated that the results simulated by coupled wave-tide-surge model are closer to the measured and particularly in excellent agreement in the extreme values of the wave heights and set-up. This study shows that the radiation stress can increase the wave heights maximally to 67cm and sea level to 40cm. It is also found that there are areas of over 50cm wave height increase and an area of over 20cm sea level increase in the Huanghe Delta coastal area, and this find may be very important in engineering. For this reason, it is suggested that in the practical engineering application, the coupled wave-tide-surge interaction numerical model should be prefered.