The invention provides a method for biotransformation of corn stigma with penicillium to obtain flavone. The method utilizes flavones-producing penicillium to ferment a culture solution containing corn stigma, in the fermentation process, the flavone precusor substance in corn stigma is fully utilized for biotransformation to acquire a large amount of accumulated flavone substance, and then purification is carried out to obtain high purity flavone. Specifically, the fermentation medium consists of: 30-50g of corn stigma powder, 2-5g of yeast powder, 0.5-1g of dipotassium hydrogen phosphate, 0.5-1g of magnesium sulfate, 0.5-1g of potassium chloride, 0.01-0.1g of ferrous sulfate, 0.05-0.2g of vitamin B2, 0.05-0.1g of vitamin B6, 0.05-0.3g of vitamin C, 20-40g of maltose, and the balance water added to 1L. The method provided by the invention has the advantages of low cost, high yield, high product purity and good activity, and simple operation steps, and is suitable for industrial production.