The present invention belongs to the technical field of aircraft testing. The horizon sensor tester is characterized by comprising a first single-pole single-throw switch S1, a second single-pole single-throw switch S2, a first fuse F1, a second fuse F2, a first ammeter A1, a second ammeter A2, and testing holes Va, Vb, Px, Py, Pz, Rx, Ry and Rz. According to the present invention, with the horizon sensor tester, the horizon sensor can be subjected to power consumption check, warning flag retracting time check, indication precision check, synchronizer output check, directivity check, correction speed check, correction incisal angle check and rotor stop time check so as to completely detect various performance indexes of the product.