This study was conducted to find out the effects of the germicidal action and preservation of milk drawn directly from 15 heads of Korean cows in the Taejon area under the temperature of 35℃, 25℃, 15℃, 5℃ each for 120 hours in the laboratory. The results of the acidity test, alcohol test, boiling test, pH test, methylene blue test and bacterial counts on Korean cow`s milk were as follows; 1. The acidity was 0.208% right after the milking. A sudden change occurred. The acidity content increased to 0.26∼0.36%. The same change occurred at 12 hours at 35℃, 16 hours at 25℃ and 48 hours at 15℃. There was only a slight charge of acidity(0.208-0.212) for 120 hours at 5℃. 2. The results of the alcohol test were positive after 12 hours at 35℃, 16 hours at 25℃ and 48 hours at 15℃. The results were negative at 5℃ for 120 hours. 3. The results of the boiling test were positive after 12 hours at 35℃, 20 hours at 25℃ and 48 hours at 15℃, while marking negative at 5℃ fur 120 hours. 4. The results of the pH test on Korean cow`s milk were pH 6.1, with the following changes after 8 hours at 35℃, 16 hours at 25℃ and 48 hours at 15℃. No change of pH appeared for 120 hours at 5℃. 5. The results of the methylene blue reduction test were as follows; During 120 hours of testing, the milk maintained a blue color for 8 hours just after the milking and kept it`s freshness for 120 hours at 5℃. It was also found that the milk kept fresh for 4-8 hours at 35℃, 12-16 hours at 25℃, 24 hours at 15℃. 6. The total bacterial counts of Korean cow`s milk were 440,000/㎖ just after the milking. The effects of germicidal action were presented for 4 hours at 35℃, 6 hours at 25℃, 12 hours at 15`C and 72 hours at 5℃.