Abstract: The issue of hole cleaning of horizontal wells in deep zones is difficult and important.Combined with the pracitcal situatin of X10-1 H well,the drilling fluid properties and other factors that may have an influence on hole cleaning have been analyzed.In the end,the paper put forward the hole cleaning technique for horizontal wells which covers the following issues:the structure of drilling tools should be optimized, the properties of drilling fluids should be adjusted, the drilling design and drilling speed should be properly selected and etc,and the application proved to provide guidance for the drilling of horizontal wells in deep zones.