Gasification process is one of the utilization of biomass energy is to convert the energy from the solid materials (biomass) a syn-gas (gas fuel) with limited air supply, which later can be used as fuel. There are several types of gasification is one type of downdraft gasification stove which means the direction of the air flow and gas gasification results clockwise is down. Efforts to optimize the process of gasification one only can be done by adding the isolator on gasification stove. In this research, variations isolator materials used is the pollen bricks, pollen among stones and sand. With the coat the surface of the furnace gasification, will reduce the secretion of the heat insulation on the surface of the furnace. This research aims to find out the influence of the isolator to temperature burning, and the influence of the isolator to the time a flame effective gasification stove with fuel rice chaff. The results of this study found that the average temperature flame effectiveness on a brick powder 563,9°C with temperature isolator 103,6°C and a flame effective 54 minutes. On the pollen among the average temperature flame effective 540,8°C with temperature isolator 135,8°C and a flame effective 52 minutes. While the average temperature sand flame effective 514,62°C and temperatures isolator 147,7°C and a flame effective 50 minutes
