Surface hardening of drill rod joint material 30CrMnSiA by using 2 kW power and 100 mm/min scanning velocity has been performed. The microstructure and hardness of the transformation layer have been studied. The experimental results show that the surface hardened layer consists of the hardened region and the interim region and the temper microstructure. The microstructure of hardened layer was very tiny. Its hardness is 30% higher than the high frequency quenched. Quenched depth is 1 7 mm and one time higher than the high frequency quenched