The objectives of this research aimed to study the appropriate ratio for making light weight brick which composed of the sawdust and water hyacinth and to study the efficiency of light weight brick. The research method was done by study the mechanical properties the compressive strengths and the physical properties with water absorption. The main materials were as follows: type 1-normal Portland cement lime gypsum aluminum powder ratio 30:9:9:2 and researchers determined 5 levels including of sand sawdust and water hyacinth according to the following proportions 40:5:5 30:10:10 20:15:15 10:20:20 and 0:25:25. The results revealed that the most appropriated ratio of the light weight brick was 40:5:5. The maximum compressive strength was 1.63 N/mm2. It is close to 2 N/mm2 from class 2 light weight brick standards value. The lowest value of water absorption was 514.29 kg/m3. It is close to 500 kg/m3 from water absorption of light weight brick standard value. Therefore these results supported the environmental conservation objective by increasing the economics values of sawdust and water hyacinth.