Abstract: Based on the elasto-plastic semi-analytical expressions of load-displacement relation and J integral-load relation for mode I cracks deduced from the equivalent energy principle, the J resistance curves of different components are successfully determined using the semi-analytical method. Furthermore, the J resistance curve of small C-shaped outside edge-notched compression (COEC) specimen at high temperature can also be obtained by the same method. According to the growing crack size of sharp cracked specimen determined by the semi-analytical equation, the crack tip opening displacement (CTOD, δ) resistance curves of ductile materials can also be determined.