A narrow channel setup was established and experiments were conducted to study the pre-ignition characteristics of wire insulation under overload conditions in weak buoyancy environment.The pre-ignition temperature variation trend of both the wire insulation and its nearby temperature monitoring points,the movement characteristics of smoke produced from the wire insulation and the ignition delay time of wire insulation were investigated.The results indicated that the narrow channel setup with a height of 10-15 mm was effective to suppress the effect of buoyancy,and the pre-ignition characteristics of wire insulation in microgravity could be predicted well by the narrow channel method.