Plastic greenhouses are now widely used in the cultivation of vegetables, fruits, flowers and other crops and aquaculture in coastal areas. The curve shape of the greenhouse skeleton is one of the most important factors affecting the function of the greenhouse. At present, the equipment for bending greenhouse skeleton pipe in the market basically adopts a mode and working principle, with low automation degree, low control accuracy and instability, unable to truly achieve high efficiency and high consistency of the shape of each molded pipe. The automatic pipe bending machine designed in this paper not only realizes automatic bending processing, but also ensures that the bending forming of steel tube can proceed continuously with variable curvature. In this way, the bending skeleton of steel pipe (round pipe or square pipe) can be bent into a relatively smooth curve at any Angle. The greenhouse made of this skeleton will not only increase the strength of the greenhouse, but also facilitate the lighting. Moreover, there is no need to install the support frame inside the greenhouse, which facilitates the mechanized operation inside the shed, can effectively improve production efficiency, reduce labor intensity, and obtain the maximum economic benefit.