The invention relates to a radio-voltaic nuclear battery based on 
perovskite crystals and a preparation method thereof. A nuclear battery structure sequentially comprises a 
radiation source, an anodeelectrode, a p-type 
perovskite layer, an intrinsic 
perovskite layer, an n-type perovskite layer and a 
cathode from top to bottom. In the nuclear battery structure, the 
radiation source emits high-energy particles such as beta particles, X rays and gamma rays, the high-energy particles are absorbed in the high-thickness intrinsic perovskite layer, and photo-induced 
electron / hole pairs are generatedthrough a 
photoelectric effect. The p-type perovskite layer, the intrinsic perovskite layer and the n-type perovskite layer form a PIN structure, and the PIN structure forms a depletion layer. Due toa built-in 
electric field of the depletion layer, photo-induced electrons / hole pairs generated by the high-energy particles are separated and drift towards the 
cathode and the 
anode respectively to form open-circuit 
voltage or short-circuit current.