The invention discloses an acetabular fracture reduction sciatic screw inserting safety angle locator, which comprises a datum plate, a longitudinal plate and a screw guide drum, wherein three locating needles on the datum plate are inserted into three fixed sites of a human bone, so that the locator is primarily located with the human bone; through the longitudinal plate, a theoretical maximum longitudinal section between an acetabulum and an ischium for the inserting of a reduction screw is offered; the screw guide drum, on the longitudinal plate, can swing by different angles in a mode of taking a depressive part of the ischium as a circle center, and an inserting point of the reduction screw can be constantly located in the depressive part of the ischium, so that an operator, by observing an angle mark on the longitudinal plate and adjusting different positions of the screw guide drum, can control an inserting length of the reduction screw; therefore, a reasonable and effective reduction screw length is guaranteed and the circumstance that the reduction screw, which is deflected, becomes short is prevented; effective connection and fixation between a bone fracture plate and the ischium can be guaranteed, and a connecting plate can be prevented from becoming loose; and in addition, with the application of the locator, time can be saved, the success rate of an operation can be improved and pain in patients can be reduced to a certain degree.