An embodiment of the invention discloses a rendering method based on a high dynamic range image for solving the problems that an image after being processed by an existing rendering technology is lack of a brightness change and a shape change. The method of the embodiment comprises the following steps: constructing a hollow sphere the diameter of which is greater than the dimension of a computer synthesized body; enabling an HDR background image to cover an inner surface of the whole hollow sphere; completing first rendering; constructing a plane, as a support surface, for placing the computer synthesized body in the HDR background image; completing second rendering; performing subtraction on RGB values of two rendered images, cutting out a texture region from a result image after the subtraction, and enabling the texture region to repeatedly cover the support surface; and placing the computer synthesized body on the support surface, completing final rendering through adoption of rendering incident light, and outputting an obtained final image. An embodiment of the invention further provides a rendering device based on the high dynamic range image.