Provided are a biological drying device and method having continuous material feeding and full mixing and having no heating period, said device comprising a case body (1), an stirring screw (2), and an aeration nozzle (3); said case body (1) uses a U-shaped reaction chamber as a bio-drying reaction chamber, and the stirring screw (2) and aeration nozzle (3) are mounted inside for turning and stirring, and ventilating and aerating; the stirring screw (2) uses spiral blades (2.2) to avoid plastic entanglement and blind spots in stirring; the aeration nozzle is designed to prevent clogging; said method comprises a startup solution and an operation solution; by means of completely mixing fresh and perishable waste and decomposed materials, and a reasonable distribution of micro-organisms and water, extremely high microbial biomass and microbial activity is obtained, so that the long heating period for the fermentation process is skipped, shortening the residence time and reducing the footprint, reducing investment costs and operation and maintenance costs.