The invention relates to an automatic flow adjusting valve of a grate cooler. The automatic flow adjusting valve comprises a case, a compressing mechanism, a connecting pipe, a supporting rod, a connecting sleeve, a supporting spring, a connecting plate and a guiding sleeve; an air bellow is arranged at the top of the case, and a net plate is arranged above the case; the supporting rod is inlaid in the connecting sleeve, and a pressing plate and the supporting rod are mutually fixed; the supporting spring is arranged between the pressing plate and the connecting sleeve, and one side of the pressing plate is connected with a sliding rheostat; sliding holes are formed in the two sides of the connecting plate, and a rolling shaft is arranged at the end, away from the connecting plate, of a supporting plate; a spring rod and the connecting plate are connected with each other through the sliding holes, and the guiding sleeve is arranged on the outer side of the rolling shaft; and a compressing clamp is arranged at the top end of the supporting plate, and a rubber plate is arranged in the compressing clamp. According to the automatic flow adjusting valve of the grate cooler, appropriatecold air can be configured for cement clinker at different transferring sections according to the weight, and the situations that the excess cold air is introduced, energy waste is caused, and the cost is increased are avoided.