The software productivity and quality can be improved by the systematic reuse of software. Reuse and reusability are the two important factors in the software development. Reusability is a prime principle in service oriented architecture. For realizing the reuse of service, the adequacy of ability of service reuse should be properly quantified. The quantification of reuse needs a suite of metrics and many metrics are also available. Each research and publication focuses on different qualities of service to propose a set of metrics for service reusability. This paper studies the service reusability to understand the concept and survey the reusability metrics. The purpose of the paper is exploring the available service reusability metrics for further research.