A safety receptacle for power cord includes a main body, a positioning plate, and a sheath. The positioning plate is fixed to the main body, having an elastically swayable active section. The sheath is movably sheathes the main body. The main body, the sheath, and the active section are formed with corresponding insertion holes and aperture. When the plug is inserted in the receptacle, the conductive pin of the plug is clutched by the active section so as to prohibiting slack of the plug. Additionally, the active section contacts the conductive pin by point contact, so that little dust would be produced by abrasion of the active section and the conductive pin. Without the piled dust, ignition is prevented. Safety of the receptacle is then improved.