IEC and CISPR have continuously endeavored the measurement method of Immunity Test as international unification, but not established yet. The main reason is that the measurement method and the normalization of threshold to obtain the complicated parameters for Immunity Test are difficult. Thus, the Immunity Test Setups are used differently according to the measured electromagnetic environments. This study developed an Immunity Test System and Algorithm for measurement software suitable for IEC801-3 Regulatons using ready-made amplifier, signal generator, and developes interconnecting interface board interacting with other appratus i.e., RF Switch, Power Meter, Field Sensor and Pre-amp. We are to develope an automated software using Top/Down and OOP(Object Oriented Programming) method.