The horizontal intersected well set project at Kazan Trona Mine and Beypazari Trona Mine in Turkey boasts of the largest scale in the world by far, with large amount of drilling work and huge technical difficulty. This paper summarizes the common downhole drilling incidents and complex situations that frequently occurred during drilling, such as sticking, drilling fluid loss, and breaking off drilling tools, analyzes the cause of the incidents in combination with the actual cases, compares the different results achieved by different treatment methods, and finally proposes some safe and effective measures for incident prevention and treatment. The experience accumulated on the project could be used as a reference in similar drilling projects for prevention and treatment of downhole drilling incidents.