In view of the features of an on-board embedded software,an on-board embedded software testing process model,butterfly model based on W model and X model,is proposed.This new model not only reflects the test for entire development activities,but also supports iteration and alteration.Especially,it is suitable for the characteristic that on-board embedded software development process needs multiple cycles.This on-board embedded software testing process model has many advantages in finding the design defects of software and hardware at early stage for satellite products,shortening the development cycle of on-board embedded software,reducing the costs of software and hardware and effectively improving the reliability of on-board embedded software,and it is suitable for the whole development process of on-board embedded software.