A position determining device for orthodontic implant surgery includes a base having a first and an opposite second end an impression material fitted on the base atop a fixing section thereof and having a pressure receiving surface for a patient’s teeth to compress thereon a positioning member mounted on the base and including a measuring scale formed of a radiopaque material and an x-ray film holder connected to the first end of the base and internally defining a receiving space for clamping an x-ray film therein. By arranging the measuring scale and the x-ray film in the receiving space parallel to each other and providing the teeth-compressed pressure receiving surface of the impression material, the exposed and developed x-ray film can show relative positions of the patient’s teeth and the measuring scale to assist an orthodontist in quickly understanding the positional relation between the patient’s two adjacent tooth roots.
