The invention discloses a magnetic zipper of trousers. Left and right sides of the magnetic zipper fit each other and are a magnet body part of a magnet body fully wrapped by a left silica gel belt and silica gel on the right side and a magnet body part of a magnet body fully wrapped by a right silica gel belt and silica gel on the left side respectively; the structures of the left and right magnet bodies are same, the thicknesses of the left silica gel belt and the right silica gel belt are one millimeter, the thicknesses of the magnet body parts are five millimeters, and the thickness from the silica belts to the magnet body parts is gradually increased; the two magnet body parts are parallelly arranged at the position lower than four centimeters of the upper end of the middle of the magnetic zipper and higher than two centimeters of the lower end of the middle of the magnetic zipper, the two adjacent parts of the two magnet body parts are flat surfaces, and the two flat surfaces attract each other. According to the magnetic zipper, in winter, people can more conveniently open the zipper, and the zipper can be automatically kept closed for some forgetful people.