The invention belongs to the field of autonomous path planning of robots and provides a robot path planning method based on an elliptical tangent line structure. According to the method disclosed by the invention, an obstacle area is encircled by virtue of an ellipse, binary searching of the path is performed by utilizing tangent line generation of points to the ellipse, and the searched path is subjected to smooth transition by virtue of an arc edge of the ellipse. The method comprises the following steps: bad point rejection and cost map generation on the acquired data, performing minimum encircling ellipse generation and other operations on a specific obstacle area, performing a series of processing such as tangent line generation of points to the ellipse, approximate common tangent generation of the ellipse to ellipse and the like, obtaining all alternate paths from an initial point to a target point, and finally selecting the optimal path through a cost function. According to the path planning method provided by the invention, the problems in the traditional method that the calculated quantity is great, the path is not smooth enough and the like are solved, an optimal and smooth path can be obtained in less time, and the application requirement on rapid path planning in a two-dimensional robot space can be met.