For laser welding, high energy is needed to heat metals up to a melting point. In order to stay constant a melting state, we need high power and CW(Continuous Wave). The welding of a laser can be classified by two parts, which are general welding and deep penetration welding. General welding is used for thin devices and plate, however Deep penetration welding is used for thick materials with the formation of a key hole through a lser The cutting of a laser needs more higher energy than the welding case. This cutting method can be applied to thick metals and complex forms of non-metal materials. In case of getting thiner layer, generally it is easy to cut this materials by a laser and the depth of cutting is about 0.5 ~ 2.5mm. If the thickness is less than 1.0mm, we can make the cutting with to less than 1.0mm, so we can protect modification of materials. Laser punching occurs by evaporation of materials, this case needs more energy than two previous cases. However energy density of punching is more larger, this evaporation particle can change into plasma, so when the density of plasma is increasing, this state can reflect or absorb the laser light. Because of this, it is difficult to do laser punching. Therefore In punching case, Pulse wave or Q-swithced laser beams with high repetition rate is more efficient than CW. Diode Pumped Green laser, developed by Golden Light company, is used for marking on the metals, plastic, jewel, gold, and so on. The Beam spot size of Green laser is smaller than IR lasers at a focus point, so Green lasers are very useful for micro processing, accurate marking on the surface of materials, and general marking for jewels, PCB circuit boards. Laser technology has been very delicate technology for a long time, but it is difficult to use these lasers in production line of industry. However the design of laser system has been well developed, so it is proved as efficient and trustworthy equipment and the market for a laser is fast increasing now. Especially, in comparison with original technology, lasers should have one of the following features at least. ¡á Laser in only useful tool for special materials or processing. ¡á Lasers are cost-effective and the quality of materials is more better than original processing. ¡á Using lasers, production amount should be increased through removing some old devices and improvement of a manufacturing process. Therefore in order to demonstrate the merits of laser processing technology. The close cooperation between laser designers and operations in industry should be needed. From the point, high trustworthy and cost-effective products will be available and the region of applications will be more expanded.