Hydraulic simulation is one of the critical methods to research the filling mechanism of molten metal in the casting process. However, it only performs on test pieces with relatively simple structures due to the limitation of the preparation method. In this study, the method of photocuring additive manufacturing was used to prepare the complex casting mould from transparent photosensitive resin. The pouring test was carried out under different centrifugal conditions, and the filling process of the gating system, support bars and other positions in the vertical direction was recorded and analyzed. The experimental results show that the internal liquid level and the filling process of the test piece prepared by this method can be observed clearly. The angle between the liquid surface and the horizontal plane in the test piece gradually increases as the centrifugal rotational speed increases, which means the filling process is carried out from outside to inside at high rotational speed. The velocity of the fluid entering the runner increases with the increase of rotational speed, but the filling speeds is less affected by the centrifugal speed at other positions. The liquid flow is continuous and stable during the forward filling process, without splashing or interruption of liquid droplets.