RDF is short in calculating, especially complex calculating. SPARQL Inferencing Notation (SPIN) has been proposed with a specific capability of returning a value by executing external JavaScript file that in partly performs complex calculating, however it is still far away from accomplishing many practices. This paper investigates SPIN's capability of executing JavaScript, namely SPINx framework, presents a method of equipping RDF data with a new capability of invoking REST API, by which a user who is querying can obtain returned value by invoking the REST API  performing complex calculating ,and then the value is semantically annotated for further use .Calculation of lift coefficient of airfoil is taken as a use case ,in which with a given attack angle as input a desired returned value is obtained by invoking a particular REST API while querying the RDF data. Through this use case, it is explicit that RDF data invoking REST API for complex calculating is feasible and profound in both real practice and semantic web.