Preparation method and application of polycaprolactone / natural polymer composite porous scaffold, method: including preparation of polycaprolactone electrospun nanofiber membrane; (1) placing polycaprolactone electrospun nanofiber membrane in alkaline solution reaction, soaking and rinsing in deionized water; (2) putting the fiber membrane obtained in (1) into DMTMM or natural polymer solution of DTMMM to react, immersing and rinsing in deionized water, and then immersing in natural polymer for room temperature reaction, to remove Ionized water soaking and rinsing; (3) Evenly coating and casting the mixed solution of natural polymer materials on the fiber membrane obtained in (2), freeze-drying, and extracting the solvent; (4) Applying the double-layer scaffold obtained in (3) After soaking in the cross-linking room temperature reaction, soaking in deionized water, rinsing, and freeze-drying. The porous scaffold prepared by the invention is stable, has suitable pore diameter, good biocompatibility and fast degradation rate, and can be used for skin and clinical tissue and organ defect repair, reconstruction or wound dressing.