Abstract: Due to thin sandstone reservoir and wide-distributed bottom water,horizontal well is themost common development pattern in Triassic of the Tahe Oil Field.The key factors influencing hori-zontal well development include residual oil and interbed distribution,trajectory control and workingsystem improvement.As to make good use of horizontal wells and to improve single well product andoilfield recovery,we should take reservoir accurate description and residual oil distribution as the base,use geological model and numerical simulation,improve regional well network and production parame-ter,and manage reservoir scientifically.Only in this way,can we make the greatest profit.