In farm management planning , decisions under imperfect knowledge are often inescapable, yet decision must be taken. Crops are planted without perfect knowledge of weather or markets, unpredictable economic or political events may occur. This article studied on cropping planning under price uncertainty, connected with diversification of cropping with the upland irrigation developing project in southernarea of the Osumi Peninsula of Kagoshima Prefecture in Japan. in this area main type of farming is mixed farming of rice, vegitable and beefcalf production, and each farm scale is very small, and farmers are very old. Farmers ded not expect to increase their income, because of the failure of replantation occurred in his upland. The purpose of this project is to promote the vegetable production which is one of the main crop in this area. but vegetable prices are very fluctuating. For that reason this fluctuation must be considered for cropping plan in this area. For making the cropping plan, we took the marketing research on wholesale prices of vegetables shipped from this area to Tokyo, Osaka, Fukuoka and Kagoshima Central Wholesale Markets, and then calculated farm income to each marketing case. The optimal marketing plan is made under consideration of an average income and its coefficient of variation. And for the Risk Programming Model, variance and covariance have been calculated from the income fluctuation of each crop. The E-V (expected income-variance) criterion is attractive for farm planning. The Quadratic Programming Model, as developed as a useful method to consider uncertainty in farm planning. The Quadratic Programming Model can be define as follows. (snip). Using this criterion, we obtained the set of efficient cropping plans and suggested the farmer to make the final choice. The results of this study can be summarized as follows: (1) In this irrigation project, we made a plan with an attractive effects to farming in this area. This project make increase of farm income 1.3-1.5 times in comparision with actual type of farming. (2) We compared the E-V criterion to the Game theoretic criterion, especially Sevege criterion. Svege criterion was not suitable for optaimal cropping planning to this area, becausethe most fluctuated crop was selected as a main crop in the optimal plan. Using the information of the marketing research to the E-V criterion, we found a more profitable and less fluctuant cropping plan than Savege criterion's plan.