Abstract: Gasification is a thermo –chemical conversion process in which biomass reacts in oxygen/air deficient atmosphere to produce a gaseous fual mixture.The result of gasification is the producer gas, containing carbon monoxideand hydrogen as main combustible gases.Producer gas can be used by mixing with air in internal combustion engines and in furnances for thermal applications. Gasifier is a reactor in which the gasification process is carried out. The objective of this paper is to study design and operation analysis of down-draught, open core gasifier which uses rice husk as gasification fual. Its output is about 14 kW and the design consideration is intended for YSD2100 Diesel Engine. In this paper, the components of rice husk and their operations are studied. Moreover, reactor designs, gasifier efficiency and power output calculation are included.Besides, the maintenance and safety techniques, troubles and their solutions are also discussed.