The invention discloses a gauge for three directional deformation of a ground fissure. The gauge comprises two vertical uprights which are respectively fixed at the left side and the right side of theground fissure, a horizontal tension displacement testing device which is fixed between the two vertical uprights, a vertical displacement testing device and a horizontal shear displacement testing device which are arranged on one of the vertical uprights, a data analysis system and an alarm unit controlled by the data analysis system; the vertical displacement testing device comprises a verticalslide block and a vertical line displacement sensor; the horizontal tension displacement testing device comprises a horizontal support slide shaft, a horizontal support bar, a horizontal slide blockand a horizontal line displacement sensor; the horizontal shear displacement testing device is an angular displacement sensor; and the horizontal line displacement sensor, the vertical line displacement sensor and the angular displacement sensor are connected with the data analysis system. The gauge has the advantages of convenient installation and debugging, convenient use and operation, high testing precision and good testing effect, and can synchronously detect absolute values of three directional deformations at the same point of the ground fissure.