The invention discloses an elastic rotary belt fastener comprising a rotary shaft and a rotary assembly, wherein the rotary assembly is matched with the rotary shaft in a rotating mode; the rotary shaft is connected with one end of a belt decoration panel/ belt fixed structure; the rotary assembly is arranged on one end of the belt decoration panel/ belt fixed structure; one end of the rotary assembly is provided with a spindle through hole for inserting the rotary shaft, and a containing groove vertical to the through hole; the section of the rotary shaft is in waist round shape, and two ends of the containing groove are provided with the groove in which an elastic assembly is clamped; the elastic assembly is pressed against the periphery of the rotary shaft; and by the spindle of the rotary shaft, the elastic assembly is pressed against the plane of the rotary shaft to form locking position. The elastic rotary belt fastener of the invention converts an elastic sheet groove in the prior art into the groove, so that the elastic rotary belt fastener has simpler structure and lower processing cost. Corresponding to the elastic assembly of which at least one end part is connected, the structure of the belt fastener that two separated elastic sheets of the belt fastener are clamped in the groove has small possibility of deforming and long service life. The linear elastic processing technology of the invention is simple and lowers processing cost.