Abstract: This invention relates to a method for detecting interactions between molecules, such as, biomolecules, and relates to a method for screening target molecules, both in vivo and in vitro. In this invention, the first detecting material and the second detecting material are provided, wherein the first detecting material is bound to a localizer which is translocated by externally applied driving force, and the second detecting material is bound to a label. Thus, the complex of the first detecting material and the second detecting material can be detected reversibly by changing the strength of the externally applied driving force, and the target molecule can be screened effectively.