Abstract: In order to solve the problems of serious erosion, high failure rate, and large cost of inclination measurement tools while drilling due to high drilling flow rate in upper large vertical well sections of deep and ultra-deep wells, the methods of expanding the flow area, simulation optimization of flow field, and local carbide protection in the area of intense erosion were comprehensively adopted, and a rotary valve group with large channel and erosion resistance was developed. Multistage composite vibration reduction methods such as flexible suspension fixing of accelerometer and silicone potting adhesive of circuit board were adopted to improve the shock resistance of electronic circuit of inclination measurement tools while drilling. By designing a fast transmission code, electronic circuit with low power consumption, and energy-saving operation mode, the efficiency and endurance of inclination measurement tools while drilling were improved. The key components of the rotary valve group with large channel and erosion resistance were developed, and the shock resistance, inclination measurement efficiency, and endurance of the inclination measurement tools were enhanced by different technical methods. An inclination measurement tool while drilling for vertical wells with a high drilling flow rate was developed. The tool was used to monitor the angle of inclination while drilling in 12 wells in Sichuan, Chongqing, and Xinjiang regions and showed the ability to withstand erosion due to the high flow rate. The maximum applicable flow rate of the tool reached 120 L/s, and the operation was stable and reliable. The failure rate was less than 0.5 times/month, and the battery could work for more than 30 days. The field application shows that the inclination measurement tool while drilling for vertical well sections with a high flow rate can meet the requirements of inclination measurement while drilling in large vertical well sections of deep and ultra-deep wells, providing support for obtaining high-quality vertical well sections of deep and ultra-deep wells.