A method for manufacturing a mechanical long-period fiber bragg grating comprises that following step: Step 1, an optical fiber and a winding line are prepared; Step 2, a heating rod and a heat-conducting cylindrical sleeve are prepared; Step 3, the optical fiber is placed on the heat-conducting cylindrical sleeve, the heating rod is put inside the heat-conducting cylindrical sleeve, and the winding line winds the optical fiber and the heat-conducting cylindrical sleeve together, and a long-period fiber bragg grating is formed after the optical fiber is subjected to periodic pressure imposed by the winding line; and Step 4, the heat rod can change the temperature, and since thermal expansion degrees of the heat-conducting cylindrical sleeve and the winding line are different, the winding of the winding line is tight or loose, so that the optical fiber can be subjected to different pressure, thereby controlling the strength of coupling between a fiber core and a cladding mode, and the winding line can change the resonant wavelength by changing the diameter of the winding line. The method for manufacturing a mechanical long-period fiber bragg grating has the advantages of tunable resonant wavelength, controllable mode coupling strength and erasable grating.