The present invention relates to a floating lever rod force applying mechanism which comprises the following components: a lever (2), a weight (3), a spline clamper movable end (6), a spline clamper fixed end (8), and front-and-back two frame boards (1) that are fixed, the two frame boards (1) clamp the lever (2) and is connected to the lever (2) through the fulcrum axial pin, the force points atthe two ends of two frame boards (1) are correspondingly arranged with a plurality of elongated grooves, the axial pins which slide seamlessly in the corresponding elongated slot presses on the upperend surface of the lever (2), the weight (3) and the spline clamper fixed end (6) are connected to the two ends of the axial pin in the elongated slot through a crossed connector. The force applying mechanism with the invention can eliminate the orthogonal component force on the sample, and leads to that the sample is equally in the pure drafting force-bearing condition in the whole test procedure.