The invention relates to a cylinder washing and drying machine with a condenser. The machine comprises a box body, an external cylinder, an internal cylinder, a transmission system, a heating device, a computer program controller, a distributor, a water injection slot, a U-shaped water injection pipe connecting the water injection slot with the front end of the external cylinder and a vent pipe connecting an air inlet of the water injection slot with the external cylinder, wherein the condenser is installed inside the water injection slot; an air inlet of the condenser aligns with the air inlet of the water injection slot; and the condenser has curved cavity structure inside. The invention also relates to a condensation control method of the machine. By adopting the above technical scheme, the problem that the wet hot air is directly discharged into the room is effectively solved by cooling, slowing down and condensing the wet hot air entering into the water injection slot, and the condensed water is drained out of the machine via a drainage system, thus being beneficial to environmental protection, meeting the demands of the consumers and improving the life quality.