The invention relates to a sludge bio-drying treatment technology using microbial fermentation drying. Technical problems of high electricity consumption and sever environmental pollution of present sludge drying are solved in the invention. The technology is characterized in that concentrated fresh sludge with the water content of 76-84% is dried, and the technology comprises the following steps: blending the fresh sludge to adjust the water content, adding an inoculant, and fermenting and drying the sludge. Dried sludge obtained after the drying treatment can be used to replenish soil. The bio-drying technology using microbial aerobic fermentation produced heat to evaporate water fully utilizes the biological energy of the sludge, so the bio-drying technology has the advantages of economy, energy saving, environmental protection, increased drying efficiency and shortened drying cycle.