This study tries to change the way of estimating the effect of smuggling via e-commerce on tax loss from the previous studies. All previous studies that consider the effect of e-commerce on tax loss focus their study by using the overall figure or a wide view. Most studies estimate the tax loss by considering the effect of e-commerce on the total retail sales and how much e-commerce replaces the total traditional retail trade, as the size of the proportion or the percentage. From the replacement of the traditional trade by e-commerce, the previous studies claim that this substitution causes the tax loss from e-commerce.