The impacts of different facet coating methods on the laser output powers of high-power 808 nm quantum-well ridge-waveguide Al-containing laser diodes cleaved in the air are researched and then the Catastrophical Optical Mirror Damage(COMD) mechanisms of semiconductor laser diodes and the selecting characteristics of a passivation layer are discussed.Three devices that are at uncoated,coated only by reflective films and coated by passivation layers and reflective films on their facets are compared.Obtained results show that the output power of the device with the passivation layers is 36% higher than that of the one only coated with reflective films.Moreover, the semiconductor laser diode coated by reflective film is failured at a current at 5 A, while the device coated by the passivation layers has not failure at the current 6 A.It points out that the passivation layer can effectively prevent Catastrophic Optical Damage (COD) and COMD.The coating passivation film method on the facets of semiconductor laser diodes is effective to the increase of output powers of high powers semiconductor laser diodes.