Abstract:Chinese legalist thought and western positivism law thought are influential schools of law in China and in the west respectively.There are some similarities and difference between them in the aspect of law essence,function,and the relation of law and the morality.We can get a great inspiration by a comparison between the Chinese legalist thought and western positivism law thought.The comparison is a positive inspiration to us in the process of transforming our society from ruling society to legal society.