The invention relates to the technical field of soil improvement, in particular to a method for improving hardened tobacco planting soil. The method includes the steps of firstly, planting tobacco; secondly, planting paddy rice; thirdly, applying materials and performing smoldering, to be more specific, furrowing the field after paddy rice harvesting, sequentially filling paddy rice straw, soil particles, paddy rice straw, the mixture of tobacco straw and rice hulls, soil particles, rice hulls and soil particles into furrows in a layered manner, and performing smoldering after the materials are applied, wherein the thickness of each layer is different; fourthly, finishing the soil. By the method, soil bulk density can be lowered evidently, soil total porosity and ventilation porosity can be increased, soil organic matter and total nitrogen content can be increased, the activity of soil microorganisms can be increased, the hardening condition of the tobacco planting soil can be improved, and soil permeability can be evidently increased.