A double-degree-of-freedom magnetic levitation vibration energy harvester is proposed for collecting the vibration energy of the rail vehicle axle box. Based on the basic principle of single-degree-of-freedom magnetic levitation vibration energy harvester，the basic configuration of double-degree-of-freedom magnetic levitation vibration energy harvester is designed. Based on the magnetic dipole model，the magnetic force equation of the cylindrical magnet is derived，and the dynamic equation of double-degree-offreedom magnetic levitation energy harvester system is established. Considering the strong nonlinear characteristics of the system，the amplitude-frequency response curve of the system is obtained through Runge-Kutta method. According to the measured time history and frequency distribution characteristics of the rail vehicle axle box，the core parameters of the double-degree-of-freedom magnetic levitation vibration energy harvester are designed. Frequency response characteristics are compared between the single-degree-of-freedom and the double-degree-of-freedom vibration energy harvesters. The results show that the nonlinear double-degreeof-freedom vibration energy harvester can effectively broaden the working bandwidth of the energy harvesting device，and then improve the energy collection power. Under simple harmonic vibration excitation，the output power of the double-degree-of-freedom vibration energy harvester is about 1.1 times higher than that of the single-degree-of-freedom vibration energy harvester. Besides，the working bandwidth can also be broadened by about 2.7 times. Under the measured rail vehicle axle box vibration excitation，the double-degree-of-freedom vibration energy harvester can collect 31.5 mJ energy in a station interval. The corresponding peak induced current is 14.6 mA，and the peak output power is 9.4 mW.