A Diffusion analysis method is described for the determination of alcohol content in tinctures and spirits and then, the comparison test of the official alcohol number test with the diffusion analysis method has hen carried out. Throughout this experiments, a transformed Widmark apparatus is used. It is found that the diffusion analysis method using the transformed Widmark apparatus is very simple and occapy a small space. One of the most convenient fact is many sample can be analyzed at a time with this apparatus. Experimental data indicate that 95% of alcohol content obtained by the official-alcohol number test is found in the diffusion analysis.