Flatfoot diagnosis mainly has the following methods: 1, the simplest self-check method is to take their own feet in water and step on the ground, look at the ground to form the range of footprints, if there is an arch, the footprints will form a small crescent shape; if it is a flat foot, the footprints are full, but this test method is not very professional and accurate; 2, if you want to accurately know whether the arch of the foot is collapsed and the degree of collapse, it is recommended that we go to the hospital to find the foot and ankle If you want to know accurately whether your foot arch is collapsed and the degree of collapse, it is recommended to go to the hospital to find a foot and ankle specialist, take a foot weight-bearing position of the front and side image, through the X-ray can show whether the arch is collapsed or the severity of the collapse; 3, the heel of the flat foot is outwardly turned, the parents can let the patient stand up, from the back to see if the heel is obviously and the calf axis is outwardly turned at the same angle, if it is turned outwardly turned at the same angle, there may be a case of foot arch collapse.