Abstract: The precision metrology for laser power and energy is exactly important to the development of laser technology, but different kinds of lasers have different methods for their output measurement. The history of laser output measurement is reviewed in the paper. Measurement methods and equipments for assessment of laser power and energy are introduced to solve the measurement problems of laser power and energy. The working principle and the scope of application of methods in available metrology standards for highprecision metrology of the laser power and energy are presented. Development trend for laser output metrology is given in the end.