In as much as employ activity of the laser in industrial applications specially in the drilling & cutting works, it is important to study all variables & factors that affect efficiency & speed of performance such as that processes. In this paper, the study of the focusing effect of laser beam on the penetrating & cutting speed was done, through deriving the mathematical equations, and re-wording it to demonstrating clearly the role of the focusing system on application speed, and calculate the variations of the efficiency of these processes.The results demonstrated that the application speed (penetration, cutting) affected by the changing in the radius of laser beam, these variables were studied from one hand by comparing the cutting speed with and without the beam expander, where in CO 2 laser case it raised from (1.56 mm/sec) to (7.78 mm/sec) and from the other hand by using a number of concentrating lenses in the focusing system to show its effects on the application speed. Where the focal length of this lenses has a negative effect on the degradation of the cutting speed while, it has a double negative effect on the degradation of the penetration speed, where the degradation in penetration and cutting speed (0.574) and (0.384) respectively with change in collimated lens focal length about (100 -200 mm).