A casting method, comprising the following steps: S1, obtaining molten metal by using a metal smelting device; S2, storing the molten metal flowing out from the metal smelting device in an intermediate container, and transferring the molten metal stored in the intermediate container into a crystallizer below through a gate when an amount of the molten metal flowing into the intermediate container reaches a forming amount of a part to be formed; S3, controlling the crystallizer to cool the molten metal from a liquid state to a solid-liquid mixed state, and enabling a high-temperature annular blank body with a required section to flow out from an outlet of the crystallizer; S4, arranging one or more pairs of plastic forming tools at a bottom of the outlet of the crystallizer, and performing hot rolling on the high-temperature annular blank body having fluidity by the plastic forming tools; S5, enabling the annular blank body after plastic forming to descend under the action of self gravity, wherein a chuck is used for clamping and fixing a lower end of a cooled and solidified annular blank body, and a fixed annular blank body descends along a guide sleeve on a machine frame; S6, performing local machining or finishing on the fixed annular blank body on the chuck after the plastic forming by using one or more point forming machines each comprising an inner point forming machine and an outer point forming machine which are matched with each other to obtain a locally deformed structure on a side of the fixed annular blank body after the plastic forming, and simultaneously, adjusting and controlling a temperature of a machining part by using a temperature control device that is an electric auxiliary point heater, so as to obtain an annular formed part with a locally deformed structure; and S7, after the forming is completed, supporting the annular formed part by the chuck, enabling the annular formed part to descend to a bottom of the machine frame, and taking the formed part out from the machine frame. S1, obtaining molten metal by using a metal smelting device; S2, storing the molten metal flowing out from the metal smelting device in an intermediate container, and transferring the molten metal stored in the intermediate container into a crystallizer below through a gate when an amount of the molten metal flowing into the intermediate container reaches a forming amount of a part to be formed; S3, controlling the crystallizer to cool the molten metal from a liquid state to a solid-liquid mixed state, and enabling a high-temperature annular blank body with a required section to flow out from an outlet of the crystallizer; S4, arranging one or more pairs of plastic forming tools at a bottom of the outlet of the crystallizer, and performing hot rolling on the high-temperature annular blank body having fluidity by the plastic forming tools; S5, enabling the annular blank body after plastic forming to descend under the action of self gravity, wherein a chuck is used for clamping and fixing a lower end of a cooled and solidified annular blank body, and a fixed annular blank body descends along a guide sleeve on a machine frame; S6, performing local machining or finishing on the fixed annular blank body on the chuck after the plastic forming by using one or more point forming machines each comprising an inner point forming machine and an outer point forming machine which are matched with each other to obtain a locally deformed structure on a side of the fixed annular blank body after the plastic forming, and simultaneously, adjusting and controlling a temperature of a machining part by using a temperature control device that is an electric auxiliary point heater, so as to obtain an annular formed part with a locally deformed structure; and S7, after the forming is completed, supporting the annular formed part by the chuck, enabling the annular formed part to descend to a bottom of the machine frame, and taking the formed part out from the machine frame.