In order to determine the optimum dairy feeding system, a L.P. model was developed. The program consisted of 8 variables; the daily feeding quantities of formula feed, green grass, forage, wild grass, hay silage, rice straw and substitutive feed. Also, it was formulated with 25 constraint functions. The major input data of L.P. are listed as follows. 1. Weight of dairy cow. 2. Amount of average milk production per day. 3. Daily maximum feeding quantity of each feed. 4. Production and purchasing cost of each feed. 5. Nutrient content of each feed.