Abstract: Bolts are important connection components in industry. In power plants, bolts serve under rough condition such as high temperature, high pressure, and severe vibration. Besides, they suffer from tensile stress, leading to the high possibility of crack failure and consequent serious accident. Thus, it’s necessary to find out a testing method to realize the precaution of bolts’ crack failure. So far, the most common testing method of bolts cracks is traditional Ultrasonic Testing. Compared to Phased Array Ultrasonic Testing, the former one shows disadvantages such as low inspecting efficiency, vulnerability of disturb of surface reflections, and difficulty in cracks’ recognition, while the later one has merits like electronically controlled focus and scan, high efficiency, and convenience for flaws recognition. Guided Waves transfer well in bar-shaped components, with small attenuation, to a long distance. Thus, they are suitable for bolt cracks inspection. This article talks about the research on technology combining Phased Array Ultrasonic Testing and Guided Waves. The research team made the calculation of Frequency Dispersion Curve of Guided Waves transferring in Inconel 783 bolts, and analyzed the Guided Waves’ parameters suitable for Inconel 783 bolts inspection. The results showed that modal L（0, 1） possessed the highest velocity, which was ideal to represent the flaw’s reflection. And Guided Waves transmitted at the frequency of 5MHz could be used in bolts inspection due to their small attenuation. The research team focused on the Inconel 783 bolts to design inspection procedure and parameters. A system suitable for Inconel 783 bolts inspection was developed consisting of a Phased Array Guided Waves host computer and a cylindrical linear probe with 64 elements. Related simulating testing blocks were also fabricated in two different sizes for comparative test. The results from the comparative test showed that the inspection system was capable of discovery of finding out the cracks inside the bolts, with high positioning accuracy and resolving ability.