With the continuous development of oil wells, the technology of directional drilling is developed rapidly, the requirements for accuracy and reliability ae higher and higher. According to the demand of measurement of directional drilling, the angle of inclination,tool face angle and azimuth were modeled. Three axis accelerometer and fluxgate sensor were used, data were gotten by filtering and 24-bit AD conversion, then signal collection and data processing were done by using 16-bit MCU.Software design included sampling procedures, manchester coding and data transmission. Finally,the instrument was tested. The results show that the measure precision of angle of inclination reaches ±0.1°, the azimuth reaches 1.5°. Meanwhile it has temperature measurement function and rotational speed measurement function, which meets the requirements of design and use.