This research was purposed to learn the influence of using the “Water Spons Filter” (WSF) smokestack model in case of SO2 emission decreasing rate at tofu industry in Sukun, Malang. This research was an experimental research type with Laboratorium Test design which its result be analyzed by using the of Paired Samples T Test. The result were mean of SO2 emission rate before using this WSF smokestack was 24,949 mg/m3, mean of SO2 emission rate hereafter using this WSF smokestack was 11,402 mg/m3. The existence of the influence of using the WSF smokestack to decreasing of SO2 rate (p=0,036), with decreasing value about 13,548 mg/m3 (55,06%). This SO2 rate did not impinge permanent quality of emission air (SK Gubernur Kepala Daerah Tingkat I Jawa Timur No 129/1996). Therefore, there was an effect of using WSF smokestack model to decrease of SO2 rate in tofu industry in Sukun, Malang. It is suggested that tofu industry owner used WSF smokestack model to omit the emission of its combustion process. WSF smokestack model can be used as alternative because does not add high addition cost. To other researchers, it can be use as guidance to afford same kind of research by modifying its form, substance or held a research about the efficiency of it. Keywords: decreasing of SO2 emiision rate, WSF smokestack model.