The coupling-transmission characteristics of high power laser beam through a low-loss optical fiber made in China are investigated. The fiber optic cable composed of lens-fiber-lens is developed. 200 watt output power and 90% coupling-transmission efficiency are obtained by using the quartz fiber cable with 2m length. Up to now the fiber optic cable is successfully applied to the treatment of six cases of hepatic cancer, one case of hepatic blood vessel tumour and one case of oral cavity cancer.