This paper aims to introduce the orderliness of faults. Several ordered type s are distinguished: the unity of complexity and regularity, i.e. the structural orderliness inner fault assemblage; the unity of ( temporal ) process of format ion and (spatial ) distribution, i.e. the orderliness of fault assemblages; and the process of ordered transformation from one fault assemblage to another. A brief introduction about the major kinds of classification of faults is given, and a new (quantitative) classification of faults is suggested. Based on the pr ocess of human understanding about orderliness, three historical stages of fault researches, i.e. stages of description, system and network, are divided. The fu ndamental characters and major work of fault researches in the network stage ar e discussed.