In order to evaluate the magnetic field(MF) exposure level in residential areas near high voltage power line, this research measured MF levels at 120 sites near high voltage transmission lines in Busan region, Gwangju region, Daegu region and Changwon region from July to December, 2005, and compared and analyzed the efficiencies by measuring and applying the MF emission levels of underground cables and high voltage transmission line. As a result of the investigation of the MF exposure level by the building usages, the average MF level of 17 locations of schools was 2.44~2.45mG; that of 10 locations of hospitals 6.21~12.39mG; that of 76 locations of apartments 2.55~2.98mG; and that of kindergartens and infant houses 3.32~4.21mG. As an analysis result of MF exposure level by the separated distance, the level at the right below was 5.15~8.72mG, that within 30m 3.10~3.32mG, that within 50m 2.45~2.38mG, and that within 100m 0.71~0.93mG. In order to check the difference of MF levels by the actual distance from high voltage transmission line within same building, the evaluation of the height of each floor and the MF level has shown that the MF levels were high in the order of roof, 4th floor, 3rd floor, 2nd floor and 1st floor. Comparison of MF emission intensity of underground cable and high voltage transmission line, the results has shown that underground cable has 86-94% of reduction ratio in MF reduction compared to high voltage transmission line, demonstrating higher efficiency.