The fruit of corni (Cornus officinalis Sieb.) was analyzed by ultra-performance liquid chromatography with a photodiode array detector (UPLC-PDA) and method validation for 3 major components which are morroniside, loganin, and cornuside. The optimal extraction condition for sum of 3 components was carried out response surface methodology (RSM). Experimental factors were designated by RSM and a central composite design (CCD). The suitability of the experimental model was verified by analysis of variance (ANOVA), and the regression coefficient was calculated as 0.6994. The maximum predicted value for the sum of the yields of the 3 major components was 1.555% with an extraction temperature of $70^{circ}C$ and an extraction time of 38 min in 64% ethanol. Under these conditions, the actual value was detected to 1.527% (${pm}0.034$).