This paper presents statistical analysis of radar altitude estimation error using the radio refractive index (RRI), N, in Korea. RRIs are derived from two stations, Sokcho and Baengnyeongdo, which are placed in the east and west of Korea on the same latitude, respectively. The seasonal mean values of the RRI are large in summer and small in winter, and regional standard deviations of the RRI exhibit different tendencies because two stations have different climate conditions. The radar altitude estimation errors also have the same leanings with respect to the RRI because the altitude errors are strongly dependent to the RRI. Moreover, the monthly means and standard deviations of radar altitude estimation errors rise as range increase. These results are useful to estimate and calibrate radar altitude error in Korea.