Electric and electronic parts have been increasing in the automotive industry and developing as a single or an integrated one. In addition, all the control modules are connected to the communication line and the functional error is likely to occur due to its complexity increased further. In this regard, the safety is well defined in detail on IS026262 functional standard declared as ISO standard in order to ensure the functional safety of electric and electronic system. The standard analyzes the risk factors for all the functions related to electric and electronic parts, determines the risk level, and then defines ASIL rating(A-D). The standard classifies system level, hardware level, and software level at product development and describes process, development and validation for the functional safety which may occur in each level. The purpose of the standard is to minimize any unexpected accident due to functional errors in the vehicle. The verification method by HILS system, which is the previous step before testing electric and electronic parts on the vehicle, has the advantage of less risk and lower cost than actual vehicle test. This paper shows how to verify and validate the functional safety of software by HILS system which is much used in car manufacturers as a validation method.