The major feature of context-aware applications is that the program can implement different actions according to the context environment of users.With regard to programming context-aware applications with the traditional object-oriented model, behaviors related to the context may be distributed in a program, which should be separated through branching statement, thus greatly reducing the degree of adaptation to environmental changes. This paper, after analyzing the issue of programming context-aware applications through the object-oriented model, puts forward Isotope Programming Model(IPM), which enlarges the concept of object and converts the object from the aggregation of attribute and behavior into the aggregation of attribute and a series of behavior code documents directed to different context. Each code document includes a segment of environment description information and the behavior that the object takes on in the context. The behavior separation is able to enhance the flexibility of program development and reduce environmental changes? impact on program. The analysis of IPM performances in several possible changes of the environment reveals that IPM model provides better adaptability for application development than the objectoriented model.