Abundant invertebrates of various ecological types live in the Rizhao coastal area’s wide inter tidal zones characterized by different configurations before 1990. Since the 1990s, however, development of coastal tourism, construction of power plants and docks, creation of field by enclosing beach, etc. caused great changes of the coastal environment. Because of this, the zoobenthic com munities and number of economically valuable animals in the tidal zones showed obvious changes. The animal community change was reflected by the almost complete disappearance of some animals such as Acanthochiton rubrolineatus, Arenicola brasiliensis, Notoacmea schrencki, Littorina brevicula, Vignadula atrata, Ostrea cucullata, Chthamalus challengeri, Ligia exotica, Ocypode stimpsoni, Scopimera globosa in the upper part of the tidal zone, as a result of their migration to the low and middle parts. Among the economically valuable animals, crabs (such as Portunus trituberculatus, Charybdis japonica, Hemigrapsus penicillatus, Helice tientsinensis, Gaetice depressus, Macrophthalmus japonicus, Matuta planipes) decreased by more than 50%; and shellfishes (such as Rapana venosa, Thais clavigera, Neverta didyma, Lunatia gilva, Sca pharca subcrenata, Mytilus edulis, Ostrea denselamellosa, Mactra sulcataris, Meretrix meretrix, Solen gouldii, Nuttallia olivacea) also decreased strikingly.