By using "two-distinction fuzzy Index" method, geological environment quality can be evaluated. Results gained by this evaluation method has the characteristics as continuity, high quantification and high reliability, which is easy to show the drawings on computer. Thus, it can be widely used in the whole geological environment evaluation field. Taking the area around Bohai Sea for example, by using this evaluation method, this area can be divided into 3 geological environment areas, 36 secondary regions ...