Abstract-This research investigated the effect of propan-1-ol on a performance of ethanol dehydration by using an alumina-silica composite (Al 2 O 3 -SiO 2 ) catalyst. It was compared the results to a H-Beta zeolite catalyst. Alumina-silica composite catalyst was prepared in the ratio of 60:40 by precipitation method. The catalysts were characterized using various techniques. The catalysts were tested catalytic activity over the dehydration of ethanol mixed with propan-1-ol at 1 atm of total pressure and the temperature range between 200 to 400 ºC. The results show that propan-1-ol decreased ethanol conversion and ethylene yield of the Al 2 O 3 -SiO 2 catalyst about 50% compared to the dehydration of pure ethanol over the same catalyst. Nevertheless, propan-1-ol did not significantly affect the ethylene selectivity of this catalyst. Ethanol to ethylene preferable occurred at high temperature but propan-1-ol to propylene preferable occurred at low temperature.