Employing a uniform density and thickness isosceles trapezoid-shaped cantilever beam, the central wavelength of the reflected wave of a fiber Bragg grating, which is pasted on the surface of the beam along the beam axis, is linearly tuned within the range of 1557.68 to 1564.2 nm experimentally. At the same time, the original uniform period fiber grating with a width of 0.52 nm (FWHM) is transformed into a chirped one which is with the maximum bandwidth of 2.52 nm and the chirp is tunable. The peak power of the reflection spectrum of the tuned grating decreases with broadening of the bandwidth.