Disclosed is an implant assembly having a function of preventing a screw from being unscrewed. The disclosed implant assembly comprises: a fixture implanted in the alveolar and having a screw fastening hole in a center of an upper end thereof； an abutment put on an upper part of the fixture and coupled by a connection screw； and a crown covered on the abutment to be fixed. The abutment has a screw through-hole formed in a lower part thereof, through which the connection screw passes to be screw-fastened to the screw fastening hole, and a screw insertion hole formed in an upper part thereof, which is connected to the screw through-hole and allows the connection screw to be inserted through the screw through-hole. The connection screw is inserted through the screw insertion hole and passes through the screw through-hole to be screw-fastened to the screw fastening hole such that the abutment is fixed to the fixture. A first female screw thread unit having a screw thread formed thereon is formed in an inner circumferential surface of the screw insertion hole. The crown has a second female screw thread unit which vertically penetrates and is formed to be connected with the screw insertion hole and has a screw thread formed on an inner circumferential surface. The present invention further comprises an unscrewing prevention bolt which is screw-fastened to the second female screw thread unit and the first female screw thread unit, sequentially, in order to make a lower end come into close contact with an upper end of the connection screw and prevents the connection screw from being unscrewed.나사풀림방지기능을 갖는 임플란트조립체가 개시된다. 개시된 임플란트조립체는 치조골에 식립되며 상단 중심에 나사체결홀이 형성된 픽스쳐와, 상기 픽스쳐의 상부에 놓여져 연결나사에 의해 결합되는 어버트먼트와, 상기 어버트먼트에 씌워져 고정설치되는 크라운으로 구성된 임플란트 조립체에 있어서, 상기 어버트먼트는 하부에 상기 연결나사가 통과되어 상기 나사체결홀에 나사체결되도록 하는 나사통과홀이 형성되고, 상부에 상기 나사통과홀과 연결되며 상기 연결나사가 상기 나사통과홀로 삽입되도록 하는 나사삽입공이 형성되어, 상기 연결나사가 상기 나사삽입공을 통해 삽입되고 상기 나사통과홀에 통과되어 상기 나사체결홀에 나사체결됨으로써 상기 어버트먼트가 상기 픽스쳐에 결합고정되도록 구성되고, 상기 나사삽입공의 내주면에
