The invention provides a camera distortion correction method and system based on B spline curved surface fitting and a medium, and the method comprises the steps of fixing a camera at a position which is a preset distance away from a target plane, and shooting a grid paper on the target plane to obtain a grid graph; performing image refinement on the grid graph to obtain a single-pixel skeleton network of the grid graph; finding out the lattice points in the single-pixel skeleton network to generate a Deloin triangular network, and sorting the lattice points; establishing the Cartesian coordinates according to the central lattice point, performing Cartesian coordinate rotation transformation, and calculating error coordinates of each lattice point; carrying out B spline curved surface fitting on the actual coordinates and the error coordinates of the lattice points to obtain a curved surface relation between the actual coordinates and the distortion errors in the X-axis direction and the Y-axis direction; and performing distortion correction on any picture of the target plane shot by the camera according to the curved surface relationship of the distortion error. The method is simple and efficient, and the distortion correction requirements in a fixed scene can be well met at the aspects of correction precision, correction efficiency and the like.