Abstract: Based on the current quantitative analysis course of fault complexity degree in mine ,single fault complexity coefficient represents various geologic facts and its value was less than the fact. Based on the evaluation of sheer incline area ratio and strike-slip fault area ratio about former resea rch,measure fault complexity degree could take an inclined fault interval multiply by the sum of extension length and ratio of numerical statement area. By geometric analysis,the new geometric model was put forward which represented geologic facts in truth. The results indicated that new expression ed uced from the model had no multiplicity,and was transpicuous and convenient for popularization.