According to the law of wood cracking,the color and the yield of different temperature ranges,pyroligneous acids of walnut shell were collected in different temperature ranges which respectively were 90℃~190℃,190℃~300℃,300℃~480℃ and 90℃~480℃(denoted as K1,K2,K3 and K after refined).Chemical constituents of pyroligneous acids at the three temperature ranges(K1,K2 and K3 after dehydration) were determined by Gas Chromatography-Mass Spectrometry(GC-MS),the bases were identified by Nuclear Magnetic Resonance(NM...