Abstract: To overcome limitations faced by nondestructive testing equipment and technology for detecting axis and dowel axis of large Game Equipment without its disassembling, according to the using characteristic of this kind of accessory, and using the experience of domestic and overseas research results for reference, smallangle longitudinal wave probe is used to detect in both end surface of the shaft. By doing same sample and a lot of experiments and according to the length and side surface dimension of the detected shaft, the probe kind, parameter(frequency, angle, shape) and applicable scope were deduced for ultrasonic test method. The feasibility research on detecting surface horizontal crack flaw on axis by using smallangle longitudinal wave probe showed that flaws in shaft accessories could be detected by using ultrasonic test without them being disassembled.