Succinct test script with high efficiency is one of key point for automation of embedded software testing. In this paper, we integrated object technique with automated simulation testing to propose an object-based embedded software simulation test script language (OESSTSL) and gave its features, formal description and supporting mechanism for automated embedded software simulation testing, furthermore, realized the execution system of OESSTSL, a script engine which has been evaluated on execution efficiency. OESSTSL has been applied in engineering practice, and the verification result shows that it has the capability to support the modeling of embedded software testing and reuse the existing testing resources; moreover, the script engine could meet the requirement of real-time and concurrency to realize real-time, closed loop and automated simulation testing for embedded software.