The utility model discloses a safety coupling which comprises a left half coupling, a safety coupling connected with the left half coupling through a fixing member, a right half coupling connected with the safety coupling through a shearing pin provided with a location member, and a flange shaft arranged on the right half coupling, wherein the flange shaft comprises a flange and a shaft part, the flange is fixed in a counter bore of the right left coupling, the shaft part is arranged inside the safety coupling and connected with the safety coupling through a tapered roller bearing, the top end of the shaft part is provided with a second location member, namely a round nut and a stop washer, and a 65-75mm interval is formed between the safety coupling and the left half coupling, preferably, 70mm. According to the safety coupling disclosed by the utility model, axial relative displacement of the flange shaft and the safety coupling can be reduced, and the shearing pin is not broken when a torque is lower than a rated torque, so that the advantages of safety and reliability in operation are achieved.