The utility model discloses outdoor side seam skirt expansion piece belongs to the related technical field of clothing, outdoor side seam skirt expansion piece, including wind clothes, the top of wind clothes is connected with hat through slide
fastener, and the edge position of hat is provided with the collection of
rope, the inside lower hem position of wind clothes is provided with the leg
bandage, and the setting number of leg
bandage is two, and two leg
bandage are located respectively in the inside of wind clothes and close to the position of both ends, and the inside lower hem center position of wind clothes is provided with the slit, and the reflective skirt is sewed on the slit, and the reflective skirt extends from the inside of slit to the outside of slit, and the outside of wind clothes is provided with the air -permeable bag mouth. It can reduce the clothes to the restraint of leg action, reduce the wind resistance when riding, solve the problem that the lower hem is tight when straddling, avoid wind clothes fabric tearing or seam open, simultaneously, can form effective rain -shelter, and the unfolded reflective skirt can prevent rainwater accumulation or splash wet trousers, improve the practicality of wind clothes in rainy day environment.