Abstract: In order to screen high efficiency, low toxicity and low residue fungicides onSclerotinia trifoliorum , improve the fresh grass yield ofmilk vetch , and establish the green and safe prevention and control system, the control effect of five fungicides and fresh grass yields were studied in field by the investigation ofSclerotinia trifoliorum . The results showed thatSclerotinia trifoliorum was very serious in field with the incidence rate of 88%. The selected five fungicides had good inhibition effect onSclerotinia trifoliorum , 50% Cantus WDG had the best control effect of 94.9%, 400g/L Mepanipyrim SC had the worst control effect of 55.2%. Fresh grass yield under fungicide treatment in full-bloom stage increased by 11%-31% comparing with that of CK. 50% Cantus WDG and 50% procymidone WP had better control effect, the results established a foundation for the safe use and demonstration and extension for these two kinds of fungicides.