Due to being charged or airflow blowing, airborne suspended particles deposit on the surface of conductors, which has an impact on DC corona discharge and electromagnetic environment of HVDC transmission lines. This is called electrode-contamination effect of airborne suspended particles. Under the circumstances of increasingly severe air pollution and frequent occurrence of sand-dust, fog and haze, while a couple of UHVDC transmission lines being going through planning, constructing and operating, research on the effects of airborne suspended particles on DC corona discharge and electromagnetic environment of HVDC transmission lines is important theoretically and practically. A detailed review of the literatures on electrode-contamination effect of suspended particles in the fields of transmission lines, electrostatic precipitation from the aspects of experimental methodology, corona onset characteristic, corona current and ionic flow current as well as total electric field was presented. This paper also pointed out the problems concerning the analysis of natural contaminants, the corona discharge characteristics of naturally contaminated conductors, the experimental methodology of artificial contamination, and the electromagnetic environment characteristic and the corona onset characteristic of contaminated conductors. At last, the suggestions for the future research were given.