The present disclosure discloses a method and a system for image processing. The method includes: obtaining images of a target environment captured by a robot in a preset movement trajectory according to a predefined condition; combining every two of the images having a same region into a corresponding image pair based on an initial position estimation of each of the images; producing an image seed based on the image pair; performing position optimization on the image seed; producing an image subset based on the image seed after the position optimization; and performing position optimization on the image subset based on the image seeds in the image subset. It can effectively reduce the computational complexity of image matching, reduce the calculation time, and improve the accuracy of image processing.