Abstract: The P92 martensite steel is a new type of steel exclusive for boilers and characteristic of high heat resistance capability. The steel is however liable to crack. It is crucial to find applicable nondestructive methods to evaluate the steel weld. Through a thorough comparison between various available NDT means, the author found that the combination of ultrasonic and magnetic particle testing was a good choice. Considering that the sound wave velocity in P92 steel is different from ordinary carbon steel and the difference shall generate errors in result evaluation, specially made reference blocks of P92 steel are used to test the material, and calibrations are made by using the ordinary carbon steel with pre-adjusted distance-wave amplitude curves. Experimental results proved the effectiveness of ultrasonic testing combined with magnetic powder detection for the P92 steel.