The invention discloses an automatic medicine dispensing system locating device and method; the method comprises the following steps: obtaining a needle locating image vertically taken from bottom to top; carrying out graying process on the needle locating image so as to obtain a binary image; obtaining needle end point coordinates according to the binary image; forming a displacement compensation instruction according to the end point coordinates and a preset distance between the camera and a needle bayonet; allowing a clamp part and a liquid injection part to relatively move according to the displacement compensation instruction, thus realizing displacement compensation. The device and method allow the needle to accurately insert a preset insertion position of a medicine container, so the needle can accurately and fast insert the medicine container from the preset position, thus improving medicine dispensing success rate and efficiency.