The invention relates to a purification method for straw gasified gas and equipment thereof. Equipment for separating, recycling and converting tar-containing wastewater is designed and installed on a gas producer and a purification device of the current gasifier; the equipment separates most of tar from water in crude gas firstly; and the separated tar-containing wastewater is not discharged butfully converted into combustible gas to be sufficiently combusted in a cooking stove. In the invention, a tar-containing wastewater converting device and a three-dimensional oxygen supply device are installed on the cooking stove; a small amount of tar-containing wastewater which is not separated after the gas passes through the purification device is fully converted into the combustible gas by the tar-containing wastewater converting device, and the combustible gas is delivered with other gas into a combustion chamber and combusted in three-dimensional oxygen supply environment, thus realizing zero discharge of the tar-containing wastewater in the gasified gas; the calorific value of the gas is as high as 5100KJ/Nm<3>, and the gasification efficiency is greater than or equal to 72%; and the combustion temperature is 100-200 DEG C higher than that of the current cooking stove, fuel is saved by 10-15% compared with common gasifiers, and the gas is to easy ignite, has the advantages of sufficient combustion, no release of harmful gas and energy saving and is environmental friendly.