Abstract: The chemical components of dust on the surface of highway slope PV module are analyzed and study the main influencing factors and mechanism of dust adhesion under condensation conditions are studied. The results show that the dust on the surface of highway slope PV dust is influenced by the environment,which lead to a high content of organic and plant fibers. Combined effects of condensation and organic cause formation of flat film and hydrogen bonds between the dust and surface of PV module to increase adhesion strength. In contrast,the plant fibers reduce the adhesion strength on interfaces.