Fatigue strength and life of weldment at high temperature is very important for high temperature materials used in power plants. In this study, fatigue crack growth tests were performed at high temperature to examine the effect of microstructure on the crack growth resistance in P92 steel weldment. Microhardness of the weldment was also investigated for better analysis. CT specimens were made from a welded plate with notches at different distances from the fusion line. High fatigue crack growth rates were found along the fusion line and fusion line+2mm line into the heat affected zone.