The invention provides a full-automatic three-dimensional precision positioning motion sample injector which comprises a Y-axis movement assembly, an X-axis movement assembly, a Z-axis movement assembly and a tray, wherein the Y-axis movement assembly comprises a Y-axis movement base, a Y-axis left guide rail, a Y-axis left guide rail slider, a Y-axis right guide rail, a Y-axis right guide rail slider and a Y-axis drive mechanism; the Y-axis left guide rail and the Y-axis right guide rail are connected with the Y-axis movement base; and the Y-axis left guide rail is connected with the Y-axis drive mechanism. The X-axis movement assembly and the Z-axis movement assembly comprise corresponding movement bases, guide rails, guide rail sliders and drive mechanisms. The X-axis movement base is suspended on the Y-axis movement base through connecting the Y-axis left guide rail slider and the Y-axis right guide rail slider, the Z-axis movement base is suspended on the X-axis movement base through connecting the X-axis guide rail slider, and the tray is connected with the Z-axis guide rail slider. The full-automatic three-dimensional precision positioning motion sample injector has the advantages of small occupation space, high position precision, stable performance and safety in operation, and can be applied to the accurate positioning of a sample injector device of analytical instruments in the fields such as medical treatment and public health, biological engineering, chemical pharmacy, chemical engineering analysis and the like.