In recent years, the number of completions of tight oil horizontal wells in oil field X has increased year by year. Horizontal well fracturing technology has been widely used in the development of tight oil reservoirs in oil field X. However, there are still some technical difficulties in the dynamic monitoring of horizontal wells. Monitoring is mainly for inclined vertical wells, and there are few dynamic monitoring methods and means for horizontal wells. Therefore, the production of each cluster after fracturing in horizontal wells has not been accurately monitored. To obtain the output of each cluster after fracturing in horizontal wells, analyze and evaluate fracturing effects, and guide the preparation of fracturing plans, it is necessary to conduct fiber-optic fluid production profile testing and research. Optical fiber monitoring technology for horizontal wells has developed particularly rapidly in recent years. At present, a relatively mature distributed optical fiber temperature DTS supporting technology has been formed. It is widely used in the monitoring of unconventional reservoirs in some large oil fields abroad, meeting the actual monitoring needs, and has achieved good results. better application effect. This paper expounds the basic principle and well selection principle of horizontal well optical fiber testing, and introduces the knowledge obtained in practical application. It is of great significance to accelerate the application of horizontal well optical fiber monitoring technology in the development of tight oil reservoirs in X oil field, improve the dynamic monitoring of horizontal wells and evaluate the fracturing effect.