The present disclosure discloses a method and a system for imaging. The method for imaging objects using the system for imaging. The system for imaging comprises a lens. The objects comprise a first object, a second object and a third object located at different positions on a first preset track. The method for imaging comprises: allowing the lens and the first preset track to move relatively in a first predetermined relationship to acquire a clear image of the third object using the system for imaging without focusing, the first predetermined relationship is determined by a focal plane position of the first object and a focal plane position of the second object. The aforementioned method for imaging is high in imaging efficiency and is capable of fast focusing according to the first predetermined relationship even if focus tracking fails so that the blurring of a photographed image due to defocusing is avoided.