The storage type fiber optic gyro inclinometer is mainly intended to solve the problems of the inclinometer in borehole trajectory measurement in ultra-high temperature and ultra-high pressure environments, covering measurement of inclinations, azimuths, toolfaces, and temperatures at different drilling depths. It is desired to overcome some technical difficulties, such as the adaptability of the combined system of the fiber optic gyro sensor temperature drift and fiber optic gyro inertia measurement unit to down hole conditions, outfield calibration, error analysis and correction. An ultra-high temperature drilling trajectory measuring instrument has been developed, which can work at ambient temperature of 270℃ and ambient pressure of 120MPa. It has been used in high-temperature geothermal energy drilling, dry hot rock drilling, scientific drilling, and deep exploration drilling for mineral resources and oil and gas resources. With extension of its use, it will be able to provide technical support for ultra-high temperature drilling trajectory measurement.