The convection drying experiments were carried out on the dewatered sludge and the advanced anaerobic digestion biogas residue by hot air convection drying technology. The effects of hot air temperature, flow rate, and sample thickness on sludge drying were investigated. The results show that the drying efficiency of sludge after the advanced anaerobic digestion is higher than that of dewatered sludge under the same conditions. The maximum drying rate of the advanced anaerobic digestion biogas residue was 486.2 mg/(g·min), which was 6 times of that of dewatered sludge 80.7 mg/(g·min) under the hot air temperature 120 ℃, flow rate 6 m/s and sample thickness 10 mm. In the actual treatment, the sludge may be first subjected to the advanced anaerobic digestion, and then reduced by means of drying.