Abstract: This study examined the effects of different proportion mixtures of methanol and gasoline fuel on emissions of conventional pollutants from vehicles with original catalysts and vehicles retrofitted with new catalysts. Testing was carried out according to China’s national standard GB 18352.3-2005, “Limits and measurement methods for emissions from light-duty vehicles,” using the Type Ⅰ testing methodology regulation for gasoline and mixed-fuel gasoline-methanol vehicles. Research and analysis focused on transient emission characteristics results. The results showed that CO and HC emissions from methanol-fueled vehicles were lower than those from gasoline-fueled vehicles, while NO_x emissions were generally higher and increased with increasing the proportion of methanol. When a new catalyst developed for methanol vehicles was used, as the proportion of methanol in the methanol-gasoline mixture increased, emissions of all three pollutants were significantly decreased. Emissions of CO from methanol-fueled vehicles mostly occurred during the first drive cycle 195. Transient emissions of HC closely followed those of CO. Emissions of NO_x generally peaked during very fast acceleration phase and the EUDC cycle.