The invention discloses a method for preparing pyrano-coumarin derivative, which takes 4-hydroxy coumarin and 1, 3-diaryl propylene as raw materials, 2, 3-dichloro-5, 6-dicyano-1, 4-para-benzoquinone (DDQ) as oxidant, and 4 A molecular sieve as accelerating agent; the raw materials, the oxidant and the accelerating agent are added into organic solvent to be stirred for reaction for 0.5-1.5h; after the reaction, the organic solvent is removed by reduced pressure concentration; then, after being purified by column chromatography, the pyrano-coumarin derivative with higher yield can be obtained.The method has mild reaction condition, high yield, simple technique as well as convenient and fast operation.