Software as a service is becoming a popular research field in software development for its feature of low costing entry, easy implementation and zero infrastructures. SaaS is a multi-tenant model which is different from traditional software in user data security, software development and deployment. In this study, we analyze the SaaS application architecture and developed a SaaS-based restaurant management system. The result shows that the SaaS-based restaurant management can meet the requirement of tenant isolation and reduce the costs for users and services providers. The SaaS-based restaurant management system provides references to other software provider to develop SaaS-based application.