The invention provides a transmission line 3D scene simulation method and a transmission line 3D scene simulation system for webpage display. The transmission line 3D scene simulation method for webpage display comprises the following steps: constructing a 3D line structure model of transmission line facilities according to the function information and structure information of the transmission line facilities; acquiring the terrain information of the earth surface where the transmission line facilities are located, and constructing a 3D earth surface model according to the terrain information; and using a graphics engine and a web plug-in to construct a 3D space scene, and loading the 3D line structure model and the 3D earth surface model in the 3D space scene to construct a 3D scene of the transmission line. According to the technical scheme of the invention, the transmission line facility and the earth surface where the transmission line facilities are located can be combined and displayed through a 3D model, and the transmission line facility and the earth surface can be displayed through a webpage.