The invention relates to the field of teaching equipment, and aims to provide a gravitational acceleration measuring method and a device thereof. According to the gravitational acceleration measuring method and the device, a laser transmitting device replaces a traditional ticker timer, thereby realizing no-contact ticking, reducing effect of a friction resistance of a traditional tape belt, and realizing more accurate experiment result. The gravitational acceleration measuring method has beneficial effects of simple structure and convenient operation. Ticking on a falling object which is coated with fluorescent powder is realized through the laser transmitting device, thereby realizing visual and obvious phenomenon and high stability. The gravitational acceleration measuring method is suitable for self research and self experience of a student, thereby improving persuasiveness in teaching. The falling object can automatically return to normal after a certain time period. High repeatability is realized, and furthermore consumable materials are greatly saved. Through a strange optical phenomenon of making the falling object emit light by means of the laser transmitting device, attention of the student can be focused to the experiment, thereby improving studying enthusiasm of the student and improving teaching effect.