The mutation testing focuses on the most possible mistakes of the software and so it has high ability to expose mistakes. However, at present it is still mainly used in procedure-oriented program testing. In recent years, object-oriented programming becomes more and more popular. This paper sets up the concepts for two new kinds of class level mutants for object-oriented program testing. One kind is of attribute mutants. The other is of method mutants. The formal description for the concepts is presented and the algorithms for generating attribute mutants and method mutants are proposed in this paper. A tool prototype for the algorithms is implemented and the related testing adequacy is also analyzed.