The optimized extraction conditions had been found through the single factor experiment and orthogonal test. The best extracting conditions were as the followings: roots were obtained by 75% alcohol with the liquid/solid ratio of 1∶8 for 35 min extraction under 85% of ultrasonic frequency. Stems were obtained by 85% alcohol with the liquid/solid ratio of 1∶8 for 30 min extraction under 75% of ultrasonic frequency. Leaves were obtained by 55% alcohol with the liquid/solid ratio of 1∶10 for 40 min extraction under 85% of ultrasonic frequency. From June to September, the content of artificially cultivated Chelidonium majus roots was higher than wild one. However, the chelerythrine in stems of artificial cultivation was lower than that of the wild. For leaves, chelerythrine content of the wild was higher than the artificial in June and July, the condition in August and September was opposite. The chelerythrine extracts displayed a certain inhibitory effect on Bipolaris maydis, Pestalotiopsis sp.,Septoria microspora, Fusarium oxysporum f.sp.lycopeersici,Fusarium bulbigenum, Curvularia lunata.