PROBLEM TO BE SOLVED: To provide a novel plant disease control composition and a plant disease control method.SOLUTION: A plant disease control composition comprises isopyrazam and alkyl polyglycoside. The weight ratio of isopyrazam and alkyl polyglycoside preferably is 1:100 to 100:1. Provided are a method for controlling plant disease by treating plant or soil with isopyrazam and alkyl polyglycoside simultaneously or in close succession, and a method for enhancing plant disease controlling effect of isopyrazam by treating plant or soil with isopyrazam and alkyl polyglycoside simultaneously or in close succession.