Abstract: In order to improve the availability of sensor data and intelligence of robot service, methods for sensor data mapping based on SSN (semantic sensor network) ontology and for Web service composition in dynamic heterogeneous intelligent service environment are proposed. Firstly, a sensor data ontology model in intelligent space is established using SSN ontology technology. The sensor annotation and semantic mapping language (SASML) is adopted to map dynamic sensor data into SSN ontology files automatically, and conversion of the physical information into cyber information is realized. On this basis, with the theory of service-oriented computing, intelligent space service model can be realized by the Web services which will package heterogeneous devices into unified function interfaces. Finally, dynamic Web service composition is implemented using the non-backtrace backward chaining (NBBC) algorithm to provide complex services for users. The experimental results in intelligent space show that the SSN ontology model constructed can effectively integrate sensor data information, and the service composition algorithm to combine single simple service components into complex service sequences can significantly improve the intelligence of robot services.