Abstract: For the purpose of being used in satellite, the authors have improved a type of fuse (Model RF2-9-0.2A) that looks like a resistor. Then a careful observing of fusing process was made, under the condition of being used in satellite we took the environmental experiments and life test. The results show that when used at half of the specified current, the improved fuses are able to satisfy the reliability required of satellite. The conditions of microgravity and vacuum would not affect it's fusing property largely. The fusing current of the fuse-wire is less than the specified value of the battery, cable and connecting element in satellite. If the problem that the heated fuse-wire touches the inner surface of the porcelain tube is solved, the fusing property will be improved further.