The properties for a normal object scheme forest with respect to a conflict-free set of ODs are shown in this paper. Firstly basic concepts and properties about object dependency, a conflict-free set of object dependencies, normal object scheme forest and the algorithm of normalization design for complex object schemes are summarized. Then the properties for a normal object scheme forest with respect to a conflict-free set of ODs are presented and proved: P(F) is a unique split-free path set for a normal object scheme forest;M<=>OD(F)<=>P(F);and P(F) is α-cyclic.There is a siginficion in the development for the object-oriented information systems.