The equipment used to carry out Non Destructive Testing (NDT) examination have played a significant role, as they have rapidly evolved to fulfill the requirements of the industry as well as to adapt to new materials and manufacturing technologies. To a great extent, the development of the robotics in the last 30 years has made this evolution possible, contributing to optimize the critical component inspection time in terms of quality and productivity. The safety operation and significance of reactor vessel is obvious to the nuclear power station. The application of NDT mechanized equipment is a key factor to enhance the safety, reliability and availability of the reactor vessel for a cost and time effective operation. According to requirement from code and the authority concerning detailed ultrasonic inspection requirement, Reactor Pressure Vessel (RPV) need to performance full scope examination for different position during PSI and ISI period. At the same time, consider RPV component have high radiation, RPV inspection machined usually was in operation wholly submerged in primary water, the machine is composed of different function parts, mechanical and control system, ultrasonic data acquisition and evaluation system and television testing system. This paper introduces how to choose and define some basic ultrasonic parameters, for example: choose probe frequency, define probe angle and for different depth use different focus probe to cover full sound path between 6dB focus lengths. Finally, preset a simple brief about typical function of ultrasonic data acquisition system and evaluation system.Copyright © 2010 by ASME