Abstract: This paper describes the characteristics of horizontal well measurement technology, and tries to present some methods to improve the measuring accuracy based on both field operations and case studies. Comparing with conventional directional well, horizontal well measurement is more difficult and complicated, and its requirement on measuring accuracy is stricter. For short radius horizontal sidetracking well, this is especially true, because it’s difficult to adjust in the relatively short interval, and the horizontal section as long as several hundreds meters must be covered in the target area. Thus precise target hitting is difficult to achieve without improving the measuring accuracy. Some items that should be paid attention to in field operation are also discussed.