The invention relates to a 2*2 mechanical optical switch based on optical fiber arrays, which comprises a substrate, a first optical fiber array, a second optical fiber array, a laser, a detector and two piezoelectric ceramics; the substrate is provided with a groove, and two wings are arranged on two sides of the substrate; the first optical fiber array is fixed on one side of the two wings, andan optical fiber is inserted in the first optical fiber array; the second optical fiber array is positioned on the other side of the two wings, another optical fiber is inserted in the second opticalfiber array, the odd number of the second optical fiber array is a first group of optical fiber channels, and the even number thereof is a second group of optical fiber channels; the laser is connected at the first channel of the first optical fiber array; the detector is connected at the sixth channel of the first optical fiber array, and the detector and the laser are combined with each other and used for detecting the coupling efficiency of the optical fiber groups of the two groups of optical fiber arrays; and the two piezoelectric ceramics are fixed at two ends of the second optical fiber array and used for adjusting and fixing the positions of the optical fiber arrays.