The invention belongs to the technical field of automobile component test equipment, and specifically relates to a measuring method of the invasion amount of a collision test of a B-pillar. The methodincludes steps: installing the B-pillar on a positioning rack, wherein the B-pillar arranged on the positioning rack has an installation form on an automobile; installing more than one laser displacement sensor on the positioning rack in sequence along the vertical direction from top to bottom, wherein the laser displacement sensors correspond to measuring points on the B-pillar; colliding with the B-pillar with a set collision speed, and acquiring data by the laser displacement sensors; after finishing the collision of the B-pillar, stopping acquisition and outputting the data by the laser displacement sensors; and drawing a displacement change curve of a test point of the B-pillar according to the outputted data, and obtaining the invasion amount of the test point of the B-pillar according to the displacement change curve of the test point of the B-pillar. According to the method, the test data is accurate and comprehensive.