The invention discloses a combustor capable of laterally feeding biological particles. The combustor comprises a combustor body, an air blower, a vaporizing chamber, a feeding inlet, a slag outlet, a ventilation chamber, a small hole, and a combustion hole, wherein the air blower is arranged on the combustor body, the vaporizing chamber penetrates through the side wall of the combustor body, the feeding inlet is formed at one end of the vaporizing chamber, the slag outlet is formed in the other end of the vaporizing chamber and is opposite to the feeding inlet, the ventilation chamber is arranged below the vaporizing chamber, the small hole penetrates through the bottom surface of the vaporizing chamber, and the combustion hole is formed in the top of the vaporizing chamber; an sufficient oxygen hole is formed in the inner wall of the combustion hole; an air outlet of the air blower is communicated with the sufficient oxygen hole and the ventilating chamber. The combustor capable of laterally feeding biological particles has the advantages of being less in fuel waste, high in benefit, capable of automatically discharging slag, sufficient for oxygen supply, smokeless, energy-saving and emission-reduced, and environment-friendly.