Along with the improved accuracy of MEMS gyroscopes and accelerometers in recent years, JAXA has been studying a navigation-grade Inertial Measurement Unit (IMU) using MEMS gyroscopes and accelerometers for launch vehicles. One issue regarding application of the MEMS IMU for launch vehicles is how to maintain measurement accuracy under high vibration environment during the launch phase. We thus developed a trial model of high accuracy MEMS IMU and evaluated its measurement accuracy under a high vibration environment by conducting random vibration tests. This paper presents the issues of the MEMS IMU for launch vehicles, trial model of the MEMS IMU, and evaluation results of the MEMS IMU under a high vibration environment.