The invention discloses a 
solar cell with a composite 
dielectric passivation layer structure and a preparation process thereof. A 
silicon oxide film, an 
alumina film and a 
silicon nitride or 
silicon oxynitride film are deposited in turn on the front, back and sides of a p-type silicon substrate to form a composite 
dielectric film on the whole surface, and windows are opened locally to lead electrodes out. Through aluminum 
oxide, 
silicon dioxide, 
silicon oxynitride, 
silicon nitride with different refractive indexes and a back surface 
passivation layer with a laminated structure of the materials, the back surface 
recombination rate is greatly reduced, the back 
reflectivity is improved, the CTM of a module is reduced, and the 
light attenuation and heat-assisted 
light attenuation and the anti-PID performance of the 
cell are improved. The structure can be made on a 
boron / 
gallium-doped p-type 
monocrystalline silicon, p-type 
polycrystalline silicon or p-type monocrystalline-silicon-like substrate, and a 
passivation method based on the composite 
dielectric film passivation structure can be used to manufacture PERC cells, double-sided PERC+ cells and imbricate PERC cells. Based on the preparation process steps and sequence, the corresponding preparation mode and the process parameter range of the laminated structure, the making of the 
cell can be well completed.