Abstract: Fourier series expansion and half-ridge membership function were used to compute the fuzzy reliability of an aviation fuel nozzle under a fuzzy safety state. The fuzzy safety state is defined by fuzzy generalized strength. When using this method, the possibility of obtaining an exact solution is improved and computational complexity is reduced. For fuel nozzles under normally distributed thermal stress, the fuzzy reliability computed by Fourier series method was more accurate than that computed by the numerical integration method. Also, computational capability was validated to be greater than numerical method. The multiple series approach offers more stable computation, while generating a lower error rate. Thus it is suitable for fuzzy safety state reliability analysis.