The invention discloses a casting process of a plate grid of a lead-acid storage battery and belongs to the technical field of machining of the lead-acid storage batteries. The casting process comprises the following steps: preparing a plate grid alloy solution from the following components in weight percent: 0.946% of tin, 0.02% of lanthanum, 0.01% of yttrium, 0.01% of cerium, 0.003% of silver, 0.003% of manganese, 0.002% of barium, 0.002% of iron, 0.0015% of chromium, 0.0015% of silicon, 0.001% of potassium and 99% of lead; spraying a de-molding agent in a pre-heated mold cavity; casting by using a casting machine to prepare the plate grid. According to the casting process, by adding the tin, rare earth elements, the silicon and the potassium into the lead, the coefficient of thermal expansion is reduced, so that the plate grid is not easy to deform when being circularly charged and discharged; by adding the silver, the manganese, the barium, the iron and the chromium, the adhesion force between the plate grid and an active substance can be enhanced, so that the active substance is not easy to fall off, and deep charging and deep discharging capabilities of the storage batteries are facilitated and the circular charging and discharging service life is prolonged.