The invention discloses a method and system for direction reduction of wet process zinc smelting slag. The method includes the steps that the dry zinc leaching slag is mixed with coal and limestone, and a mixture is obtained; the mixture is subjected to first pelletizing treatment, and first mixed material agglomerate is obtained; the first mixed material agglomerate is wrapped in calcium oxalate powder to be subjected to second pelletizing treatment, and second mixed material agglomerate with a calcium oxalate outer layer is obtained; the second mixed material agglomerate is subjected to reduction roasting treatment, and smoke containing silver, lead, zinc and indium and a metalized pellet is obtained; and the metalized pellet is subjected to ore grinding magnetic separation treatment, and a metal iron product is obtained. According to the method, the limestone is added to the ingredients so that reduction of iron can be promoted, the slag melting point is reduced, volatilization of lead, zinc and silver is promoted, and the sulfur content of the iron product is reduced; and meanwhile, pelletizing is conducted in a step-by-step manner, the calcium oxalate outer layer is formed on the surface of the second mixed material agglomerate, escaping of SO2 in the second mixed material agglomerate is reduced, and melting of the second mixed material agglomerate is effectively prevented.