The invention discloses an acid adding funnel for a lead-acid storage battery. The acid adding funnel for the lead-acid storage battery comprises a funnel body, insertion plates, a rubber nozzle, an acid adding opening and supporting frames. Grooves are formed in the inner side of the funnel body. The insertion plates are fixed in the funnel body through the grooves. The bottom of the funnel body is provided with the acid adding opening and the supporting frames. The rubber nozzle is arranged on the acid adding opening. According to the acid adding funnel for the lead-acid storage battery, the insertion plates are arranged in the funnel body so that the situation that the funnel body deforms due to the large size during vacuumization can be avoided; the supporting frames are additionally arranged at the bottom of the funnel body so that the phenomena of deflection, collapse and the like of the funnel body can be avoided, and the effect that the product quality is stable is guaranteed; and the acid adding opening in the bottom of the funnel body and an acid injection nozzle of an upper cover of the storage battery are connected through the rubber nozzle, so that flexible connection is achieved, and the acid injection nozzle is prevented from being damaged.