Abstract: The course principles and techniques of lasers are difficult to comprehend because of the profound theory and formulae.The output characteristics of the free-oscillating laser and the Q-switching laser were numerically calculated by Runge-Kutta method, which were presented as the examples in research-oriented teaching practice of this course.The results show that it will increase the understanding of the hard parts of this course, cultivate researching abilities, as well as inspire the studying interest of the students, by simulation of the physics process in this teaching practice.