The invention discloses a spring plate rigidity precision testing instrument which measures the rigidity of a spring plate on an electronic balance. The same kinds of spring plates on the same electronic balance have to possess the same rigidity. The rigidity of the prior spring plate is difficult to precisely measure due to the lack of a precision testing instrument, therefore, the accuracy and the stability of the electronic balance are affected. The lower part of the spring plate (2) to be measured is provided with a stress application rod (3); one end of a lever (4) acts on the stress application rod (3), and the other end is connected with a weight (6); an eccenter (5) is arranged close to the weight (6); and the upper part of the spring plate (2) to be measured is connected with a non-contact type displacement sensor (7) and a digital displayer (8). A weight rack (9) is arranged on the lever (4), and the middle part of the lever (4) is provided with a lever support (10). The invention has the advantages that the rigidity of the spring plate is accurately measured, the accuracy and the stability of the electronic balance can be ensured, and the spring plate rigidity precisiontesting instrument has convenient operation, simple structure, small volume and low cost.