The invention discloses a process for recovering copper, zinc, tin and lead by utilizing a side blown converter at the bottom. The process is characterized in that materials dosed and mixed from slag, ash, low-grade tin ore and flux are selected for use, the water content of the dosed and mixed materials is <= 3%, the dosed and mixed materials are stand-by, hot slag of a reduction furnace is added into a side blown converter, the dosed and mixed materials are added to the side blown converter, mixed with the hot slag of the reduction furnace for reduction smelting, the tin content of the hot slag of the reduction furnace and the dosed and mixed materials which are added into the side blown converter is more than 3%, and the silicic acid degree of the slag is 1-1.2. In the first stage, the lead and the tin are volatilized in the reduction smelting mode, and lead oxide and tin oxide are obtained through dust collection. In the second stage, vulcanizing agents are added, tin sulfide is volatilized, and tin oxide is obtained after dust collection. In the third stage the slag and the copper settles and are separated to obtain copper matte and waste slag, the slag is quenched through water, and the copper matte is cast into ingots. The process for recovering the copper, the zinc, the tin and the lead by utilizing the side blown converter at the bottom is strong in adaptability, capable of separating out valuable metal such as the copper, the lead, the zinc and the tin through one-step smelting, high in direct recovery rate, and low in valuable metal containing rate of the slag.