A safety gate has two frame assemblies, a shaft fixing assembly and a stretcher assembly. A relative distance between the two frame assemblies is fixed by the shaft fixing assembly first. The stretcher assembly further pushes the two frame assemblies outwardly so that the two frame assemblies tightly abut against two walls of a mounting premise and can be held on the walls securely. When the safety gate is not in use, the stretcher assembly is released to loosen the safety gate from the walls and the stretcher assembly can be moved to elsewhere. As the safety gate can be repeatedly mounted without having to readjust the relative distance between the two frame assemblies with the shaft fixing assembly, the operation of the safety gate is easy and convenient.