The work aims to study the nonlinear large deformation characteristics of the circular arc leaf spring to provide theoretical reference for its buffer design and application. Based on Euler-Bernoulli beam theory, the control equation of large deformation of leaf spring was derived, in which the initial arc radius and section angle were selected as the basic parameters of the control equation. Considering various deformations of the spring under the action of the pressure plate, the boundary conditions of the circular arc leaf spring were given, and then the deformation of the leaf springs with different vertex angles was calculated by the numerical solution. The high agreement between the theoretical results and the numerical solution showed the reliability of the calculation method. The configuration diagram of the leaf spring after deformation under different pressures and the nonlinear force-deformation curve of the spring were obtained by calculation. The leaf spring has obvious nonlinear large deformation characteristics and good damping and energy absorption characteristics, and can be used as a good alternative to traditional buffer materials in the buffer design of transportation systems.