We observed SaaS developed application by multitenancy to provide flexible customization and introduced many issues in software scalability and dynamic testing. Multitenancy demand to customizing the single instance according variability wishes among many customers. For that we proposed variable service process to customization multitenancy in runtime. It will be realize all benefits of variability concept for SaaS application. And proposed Feature metamodel to implement graphical editor and define all rules and linkages between elements of service process.