Abstract: In order to find out the influence law and mechanism of artificial reef on local tidal dynamics and other factors, according to the 25-hour continuous observation flow velocity and water level data of two stations in Dongshanhai artificial reef in July 2016, combining with numerical simulation method, we analyzed the effects of artificial reef on tidal power in the reef area and surrounding sea areas. With the simulation results before and after the reef construction, we obtained the variation trend of factors such as tidal current. The results show that the model simulation results fit well with the measured values. The artificial reef area had barely no effect on the tide constants and tidal characteristics in the survey area after completion. Some of the tidal current ellipsed in the artificial reef area changed direction and turned, and there was barely no influence outside the reef area. After the reef was built, the direction of the residual current within the reef area changed little, and the overall residual current of the reef area showed a decreasing trend towards the south. The horizontal flow field near the reef area changed significantly, but the influence in outer area of the reef was limited. There was an obvious upwelling flow in the inflow area of the reef, and the maximum bottom upwelling flow reached 1.2 cm·s^–1 at the time of the tide surge, while the downwelling flow appeared at the back of the reef area.