KOH etching is a convenient method with high efficiency for characterizing dislocations in SiC. However, the etching process is often affected due to the hydrolysis of KOH. To ensure stability and reproducibility of the etching process, frequent replacement of KOH is necessary, which leads to a large consumption of the etching materials. In this study, an improved method for KOH etching technique was proposed by directly injecting dry air into the molten KOH through a bubbler, in order to quickly remove moisture from the molten KOH and enhance dissolved oxygen. The effectiveness of the method is verified by etching lightly doped n-type epitaxial wafers and heavily doped n-type substrates. The experimental results show that introducing dry air into the molten KOH during the constant temperature stage before etching the SiC epitaxial wafer accelerate the evaporation of moisture in partially deliquescent KOH and achieve a faster etching rate of dislocations than fresh KOH. In the substrate etching experiment, an increase in the concentration of dissolved oxygen in the etchant is obtained by introducing dry air into the molten KOH, which promotes the etching effect through promoting the chemical reaction on SiC surface. As a result, an etching rate of dislocations similar to that of the mixed etchant of Na2O2 and KOH is achieved. This research provides a helpful method to improve the etching effect of SiC dislocations, which would have practical value in SiC production.