The invention discloses a three-bed combination pyrolysis gasification and tar cracking integrated system for solid waste and belongs to the technical field of solid waste treatment. The system comprises a solid waste feeding system, a pyrolyzer, an oxidizer system, an oxidizer cyclone separator and a cyclone reactor. According to the system, the circulating flow of bed materials among three bed is realized by virtue of a circulating fluidized bed oxidizer, a bubbling or turbulent fluidized bed pyrolyzer and the cyclone reactor which are combined with a gas stripping tube and a sedimentation tube, and the adequate mixing between the hot bed materials and pyrolysis gas is realized by virtue of the cyclone reactor, so that the tar cracking and the gas purification are greatly promoted; by virtue of structural optimization of an oxidizer and the pyrolyzer, the mixed use of different bed materials and the improvements of a bed material circulating flow system, the gas-liquid mixing level and a feeding system, the integral pyrolysis gasification efficiency is greatly improved, the heat value of product gas is greatly increased, the tar content of product gas is greatly reduced, and high-quality clean pyrolysis gas/synthesis gas is prepared.