The invention relates to a flotation machine for coarse-grain material flotation. The flotation machine comprises a support and a flotation tank, wherein an overflow weir for foam overflowing is arranged on one side of the flotation tank. The flotation machine is characterized by further comprising a stirring mechanism and a circulating tank, the stirring mechanism comprises a stirring rod extending into the flotation tank, the upper end of the stirring rod is connected with a driving device, and a stirring assembly is mounted at the lower end of the stirring rod; the stirring rod is sleeved with a sleeve, an annular chamber formed between the sleeve and the stirring rod is used for conveying air and ore pulp into the flotation tank, the top end of the sleeve is connected with the support, and at least one pulp inlet is formed in the lower part of the sleeve; the circulating tank is arranged below the overflow weir, used for recovering the ore pulp flowing back from the overflow weir and communicated with the annular chamber. A good fluid environment is provided for separation of coarse-grain materials, the chance of adhesion of ore to bubbles is greatly increased, and the condition that fine-grain ore is not mineralized or mechanical entrainment occurs is effectively eliminated.