The invention relates to a test apparatus and test method of the stiffness of a glass fiber mat and cloth. The test apparatus comprises a pedestal, a support, an up-and-down movement platform, a sample stage and a slide rail. The test method comprises the following steps: 1, cutting the glass fiber mat and cloth to be tested according to a prescribed dimension to form a sample to be tested, and carrying out standardized pretreatment on the sample to be tested; 2, tiling the pretreated sample to be tested on the sample stage, pushing the sample to be tested to forward move for a certain distance, and upward moving the up-and-down movement platform to make the upper surface of a horizontal scale just touch the falling edge of the sample to be tested; and 3, measuring the horizontal distance of the sample to be tested through the horizontal scale, measuring the falling distance of the sample to be tested through a height scale, and calculating the stiffness coefficient of the glass fiber mat and cloth sample to be tested, which is a ratio of the horizontal distance of the sample to be tested to the falling distance of the sample to be tested. The test method has the advantages of simple and effective process, scientific test principle and high test precision, and the test apparatus has the advantages of simplicity, durability, accurate test effect, convenience, and high practicality.