Mikania micrantha has invasive alien species harmful to many plants; it natively grows in South and Central America area. But now it is found throughout Asia and India area. It has a big reproductive capacity, so several researchers ever used thermal treatment, controlled-environmental treatment, mechanical treatment and biological control treatment to inhibit Mikania micrantha growth. However, rare studies use Mikania micrantha to make building materials. In this paper we will attempt to use untreated and treated (treated by carbonization) Mikania micrantha for making building bricks. Results are shown that the optimal uniaxial compressive strength occurred as 30 wt. % of the carbonized Mikania micrantha; the optimal uniaxial compressive strength took place as 40 wt. % of carbonized Mikania micrantha with an addition of organic acid. But the fresh Mikania micrantha has a lower uniaxial compressive strength, so we used interpolation method to calculate the optimized mixing ratio would be 5:95 for the fresh Mikania micrantha. In addition, Mikania micrantha as building material has no biotoxicity for E. coli.