The invention relates to the technical field of infant testing and discloses a method for testing an infant to walk down a balance beam. During a test, a subject stands at a starting flat pad. When tiptoes of the subject are ahead of an infrared starting line device, the infrared starting line device transmits information to a timing display device through a cable so as to start timing. When the tiptoe of the subject is ahead of an infrared finishing line device, the infrared finishing line device transmits information to the timing display device through the cable so as to close timing. A processor transmits time information of a timing device to a display device. Time spent on walking down the balance beam is displayed. Meanwhile, the processor transmits speed calculation information atfixed-length distance to the display device. Speed at which the subject needs to walk down the balance beam is displayed. The method can rapidly detect whether moves of the infant are standard or not,helps reduce workload of the subject, brings joy to the infant and prompts the time spent through voice.