The effect of urice husk ash (RHA) on performance of unfired brick (UB) is investigated in this study. UB is used RHA as natural fine aggregate with a constant amount of cement follow water-to-binder ratio (W/B) of 0.5 and aggregate-to-binder (A/B) of 3. A pressure changing around 25 MPa is applied to make the bricks with size of 40×80×180mm through the extrusion technique. The bulk density, water absorption, compressive and flexural analyses are performed to determine the properties of UB in accordance with the Vietnamese standards. Consequently, the 28-day compressive strength and flexural strength ranged from 18.1 to 42.1 MPa and from 6 to 14.4 MPa, respectively. Furthermore, RHA addition significantly decreased the bulk density of UB. Excepted brick with 60% RHA, the water absorption of all samples is lower than 16% which meet the requirement of Vietnamese standards.