The invention discloses a cement kiln capable of realizing waste gasification outside the same and a gasification method thereof. The cement kiln capable of realizing waste gasification outside the same comprises a cement kiln, wherein a gas inlet of the cement kiln is communicated with a gas outlet of a waste gasification furnace; a feed port of the waste gasification furnace is positioned below an outlet of a waste conveying device; an inlet of the waste conveying device is positioned in a waste material shed; and a waste grabbing device is arranged in the waste material shed. An operating method of the cement kiln capable of realizing waste gasification outside the same is characterized in that heat generated by burning part of waste in the waste gasification furnace is used to heat the rest of the waste in the waste gasification furnace, so that the rest of the waste can be gasified. According to the invention, the defect that domestic waste is high in water content and contains complicated components is overcome, the pretreatment procedure can be greatly simplified, the treatment cost is greatly lowered, and the domestic waste treatment scale is expanded; and furthermore, no auxiliary fuel is needed. Besides, the waste feeding uniformity can be ensured, thereby being beneficial to uniform distribution in the waste gasification furnace.