The invention discloses a method for measuring the deformation of vertical rods of a high formwork supporting system. In the method, two transits are used to measure the angular variation of a measured position of a test vertical rod before and after deformation by using a method of observation set through the utilization of the horizontal angle measuring function of the transits,. The method specifically comprises the following steps: according to the test requirements and the distribution of the vertical rods, selecting vertical rods to be tested, uniformly distributing measuring points on the vertical rods, and making obvious marks on the measuring points, so that the measuring points can be observed through the transits; establishing a plane coordinate system, placing the first transit at an coordinate origin, and respectively placing the second transit at proper positions of an abscissa axis, so that the measuring points on each vertical rod can be observed in the transits; measuring the distance between the first transit and the second transit by using a steel ruler; before test, measuring the angle between each measuring point and each transit by using the method of observation set, and calculating the coordinates of each measuring point according to the angle; and after test, measuring the angle between each measuring point and each transit by using the method of observation set, calculating the coordinates of each measuring point after the vertical rods are deformed, and finally, calculating the variation value of the coordinates of each measuring point.