本文分析產品價格受到產量不確定影響而波動時,一個完全競爭廠商政府提供價格支持下的投入決策與福利水準。我們發現:若廠商為一風險趨避者,且其相對風險趨避函數不大於一,責任和價格支持制度皆具有增產作用,也都會帶給廠商較高的福利。若生產函數為固定規模報酬,且遞增的相對風險趨避函數大於一,則場珊反而會進行減產,不過此時廠商仍具有較高的福利。而越高的支持價格,旗隊產量與福利效果的影響幅度越大。我們同時對實施價格支持制度下的風險之邊際與全額效果進行研究,在適當的假定下,得到類似於Batra&Ullah(1974)與Hartman(1975)的結果。但是當生產函數為固定規模報酬,且遞增的相對風險趨避函數值大於一時,風險增加卻可能導致廠商增加勞力與土地雇用輛,進而提高產量。本文同時指出,Epstein(1978)所提的一組有關Batra&Ullah結論的反證,其實並不能成立。 This paper analyzes the behavior of the competitive firm facing output price un-certainty induced by the instability of yield under conditions of price supports. We find that if the firm has less than unit relative risk aversion then the price support program will cause output and producer welfare to unambiguously increase. However, under linear homogenous production, the competitive firm with increasing and greater than unit relative risk aversion will reduce its supply and benefit from a higher level of welfare. Sets of conditions are also derived sufficient to sign the marginal impact and the overall impact of a mean preserving spread in risk. Specifically, We show that Epstein’s counterevidence of the Batra&Ullah finding is incorrect.