The development of many highly dynamic environments, such as pervasive environments, has modified the behavior of users and consequently, their expectations of systems and applications executed in these environments. Thus, a user can connect to different places, and, each time, would like to use the functionalities offered by the physically or logically close environment. This paper proposes a novel approach for specializing strategies for choosing, and then using services in a pervasive environment. To the best of our knowledge, strategies for the use of services in a pervasive environment are dynamic but ad-hocly defined during the development phase. By changing the context, the strategy can change and be replaced by another one predefined in the application development phase. Our idea is to provide a context-aware mechanism which is able to adapts dynamically the condition and action parts of the rule of the strategy to the context without the need to specify how, during the development of applications. Only a general strategy is defined in the development phase. At run time, a dynamic specialization adapted to the context, provides a specialized strategy from the general one.