NTEC metal core trimmer line includes a metal inner core and a nylon coating out of the metal inner core. The metal core is a steel wire rope. NTEC core metal trimmer line with a tearable nylon coating adopts a structure of a steel wire rope inner core and nylon coating. When the steel wire core is worn and shortened, the operator can directly shorten the length of the nylon coating sleeve, thereby increasing the exposed length of the wire rope core and extending the service life. The length of the trimming line can be extended.