This study was performed to determine the impact of genetic factors on improving Korean cattle(Hanwoo). The data of 65,299 steers, slaughtered in Gyeongsangnam-do from 2009 to 2020, were used in the analysis. The genetic parameter was estimated with 120,066 subjects including the ones with pedigree using REMLF90. As a result, the heritability of each trait was manifested as follows; carcass weight, eye muscle area, back fat thickness and marbling score as 0.34, 0.26, 0.32, and 0.57, respectively. The genetic correlation of carcass weight and eye muscle area was 0.634, showing a high degree of positive correlation. Eye muscle area and back fat thickness manifested a low degree of negative correlation at –0.028. Eye muscle area and marbling score showed positive correlation at 0.503. Marbling score showed a high heritability at 0.57, which indicated that current direction of improvement focuses on improving the meat quality, in so much that it would be possible to improve the meat quality efficiently. The improvement of Hanwoo must continue in this era of liberalization. The quality improvement among all efforts is deemed important. The studies for improvement must be conducted persistently.