Abstract: As an effective hydrocarbon production technology, horizontal injection is more and more applied in various complicated reservoir development, just like oil prodcution of horizontal wells. Taking the practical block of thin reservoir with ultra-low abundance as an example, through theoretical analysis, numerical simulation and field experiment, the injection-production regularity of horizontal wells in thin interbedded reservoir has been studied. The results indicate horizontal injection can form linear uniform displacement, prolong the breakthrough time of water injection, enhance waterflooding sweep efficiency, reduce injection pressure and improve development effect. Taking M well area of Zhaozhou oilfield as the example, it is believed that the key adjustment object should be focused on water injection wells. By reasonably adjusting injection volume or sealing water-injection layers with high permeability, the decreased water cut of horizontal single well can be easily realized.