Compared with ordinary software

the on-board embedded software has more requirements of software reliability. The software testing process model is a necessary means of improving software reliability. And it can guide us to test software in a scientific process and method. Therefore

in view of the features of on-board embedded software

this paper proposes an on-board embedded software testing process model - Butterfly model which is based on W model and X model. This new model not only reflects the test for entire development activities

but also supports iteration and alteration. It is especially suitable for the characteristic that on-board embedded software development process need multiple cycles. This study provides strong supports for effectively developing on-board embedded software and ensuring higher reliability requirements.