The invention discloses high-reliability PERC back silver conductive paste for a crystalline silicon solar cell and a preparation process for the high-reliability PERC back silver conductive paste. The viscosity of the slurry is 20 to 80 Pa.S, and the paste contains the following components in percentage by mass: 0.1%-0.3% of an inorganic additive, 1%-5% of glass powder, 45%-65% of silver powder,2%-6% of ethyl cellulose, 1%-5% of terpilenol, 20%-35% of texanol ester alcohol and a proper amount of an organic additive, wherein the glass powder is formed by the mixing of glass powder I and glasspowder II. The preparation method comprises the following steps: uniformly mixing the organic additive, ethyl cellulose, terpilenol and texanol ester alcohol under the water bath condition to obtaina carrier; adding the mixed glass system and the inorganic additive into the carrier, and uniformly mixing the mixture; and adding the silver powder system into the system at the step 2, and performing uniform mixing, rolling and filtering to obtain the back conductive silver paste. According to the invention, the PERC back silver paste guarantees the characteristics of the traditional non-contactsilver paste, is fewer in damages to an aluminum oxide passivation layer, is high in welding reliability of a back silver paste sintered electrode due to the fact that a mixed glass system is adopted, and has excellent comprehensive performances under the condition that the actual temperature is 740 DEG C-780 DEG C.