The test of the legacy substation is 1:1 functional test of each device using I/O physical signals such as voltage and current, while digital substation automation system requires complex n: n test for each IED to verify not only function of IED but also function of communication between the IED and other IEDs, and the IED and HMI using the same data. Further, an engineer involved in the SAS test should consider not only his/her own knowledge and skill for the test but also other factors form the system level view of SAS. Due to this, it is necessary and important to assure a common testing method for sharing information and dealing with the integrated system functions for the SAS test and this paper proposes the efficient model-driven testing technology and a test design system built based on the proposed.