Grid computing is a new paradigm for distributed computing, and service has become building block of grid applications. However, current approaches can not free developers from low-level laborious work when building grid applications. We propose a serviceoriented virtual machine called Abacus Virtual Machine to simplify the task of grid application development. As a language level virtual machine, it provides a service-oriented instruction set to abstract the operations on the services of a grid application. It also virtualizes services and creates a virtual global system image for grid applications, thus services can be transparently distributed and shared. In this way, Abacus Virtual Machine hides the cumbersome underlying details from programmers and reduces the complexity greatly in grid application development.