A laser pointer includes a human-machine interface disposed above the housing for users to control components inside the housing to decide patterns and size of the projecting image. The components consist of a frequency/phase control module, a driving energy control module, a laser beam generating module and a light scanning device. The frequency/phase control module controls the driving energy control module while the driving energy control module controls driving energy of the light scanning device. The size of the image is controlled by change of the amplitude of the light scanning device while the amplitude is changed along with the driving energy. The amplitude may also change along with the driving frequency. When the driving energy is fixed and the driving frequency is close to the resonant frequency, the amplitude increases. On the contrary, the amplitude decreases.