Non-contact nondestructive testing method for bridge structure

The invention discloses a non-contact nondestructive testing method for a bridge structure. The non-contact nondestructive testing method includes: determining a detected part on the bridge structure, fixing a shooting position, obtaining a reference gray level image and a target gray level image of the detected part when an engineering structure bears different loads; determining a reference module and a central pixel point of the reference module in the reference gray level image, searching a set target module throughout the whole target gray level mage through a correlation function, when a correlation coefficient of the correlation function is minimum, determining a target module and a central pixel point of the target module, accordingly obtaining the pixel distance of the central pixel point of the reference module, and converting the pixel distance into actual displacement. The non-contact nondestructive testing method for the bridge structure achieves non-contact nondestructive testing of the engineering structure, cannot cause damage to the structure and saves manpower and material resources.