The laser machining were carried out on unsatulated polyester by using CO_2 and Nd-YAG lasers. And the machined holes were observed to study the influence of the wave length of laser. The polyester was cracked by the heat shock and the hole was not formed by using YAG laser. The holes can be made by CO_2 laser without crack. The CO_2 laser machinings were performed by using some parameters, including irradiating time, power of laser and the defocusing, which influence the shape and size of the holes.