Automatic single yarn strength tester controlled by computer, used for the determination of polyester (polyester), polyamide (nylon), polypropylene (polypropylene), cellulose fiber and other chemical fiber filament and deformation silk, cotton yarn, air spinning yarn, ring spinning yarn and other cotton yarn, BCF carpet silk, The physical indicators such as breaking strength, breaking elongation, breaking strength, breaking time, initial modulus and breaking work of single yarn such as sewing thread are compatible with Windows 7/10 32/64 computer operating system and equipped with large screen touch screen. After the machine and computer software are connected, parameters can be set on the touch screen. Also can operate on computer software, data acquisition and processing automatic output.