NOVELTY - Solid bio-fuel comprises potato residue and straw as primary raw materials, and suitable additives. The preparation of the solid bio-fuel comprises (i) taking straw with water content of less than 14%, and crushing into particles (10-30 meshes) by using a crusher for future use, (ii) mixing the fresh potato residue or the old and dried potato residue with the straw, potassium nitrate and aluminum oxide after a primary dehydration treatment, (iii) cold-pressing and curing-forming, and (iv) performing post drying treatment by pouring out the formed fuel, drying and airing in natural air.    USE - Used as a solid bio-fuel.    ADVANTAGE - The solid bio-fuel is cost-effective, has safe preparation, ensures convenient civil and industrialized production, realizes transformation and utilization of the potato residue in a short time, promotes energy conservation of potato starch factories, and efficiently protects the ecological environment as compared to that of the conventional resource utilization technology for the potato residue.    DETAILED DESCRIPTION - Solid bio-fuel comprises potato residue and straw as primary raw materials, and suitable additives. The preparation of the solid bio-fuel comprises (i) taking straw with water content of less than 14%, and crushing into particles (10-30 meshes) by using a crusher for future use, (ii) mixing the fresh potato residue with the straw, potassium nitrate and aluminum oxide after a primary dehydration treatment in a mixing ratio of 1:(5-12):(0.05-0.12):(0.05-0.15), or mixing the old and dried potato residue with the straw, potassium nitrate and aluminum oxide after the primary dehydration treatment in a mixing ratio of 1:(2-12):(0.05-0.12):(0.05-0.15), (iii) cold-pressing and curing-forming by cold-pressing the mixture obtained from the step (ii) in a material tester of a forming mold at a molding pressure of 30-50 KN for 10-20 seconds, and (iv) performing post drying treatment by pouring out the formed fuel, drying and airing in natural air to make the water content to less than 14%, where if no liquid combustion improver is added, then the ignition time of the fuel is 6-8 minutes, and the calorific value is 4000-4700 kcal.