Abstract: At present, researches on saturated iron-core superconductive fault-current limiter（SISFCL） ignore its influence on fault features, frequency variation distance protection, negative sequence directional protection and the interrupting capacity of circuit breakers of transmission lines. Taking a 500 kV double-ended power system with SISFCL as an example, we systematically analyzed the characteristics of short-circuit current harmonic of different fault types, positions and initial phase angles. The characteristics include frequency distribution, harmonic content, distortion rate and time decay constant. The influence of SISFCL on the above-mentioned line protections and the interrupting capacity of circuit breakers are studied and verified based on simulation. The results show that after the SISFCL is deployed, the low-frequency and odd-order harmonic content of the short-circuit current increases during the steady state of the fault without attenuation, and the even-order harmonic time attenuation constant increases, resulting in more complicated fault characteristics. Thus, the SISFCL has an adverse effect on the correct action of distance protection and negative-sequence directional protection, while improves the fault-interrupting capacity of the circuit breaker. Finally, based on the analysis of the influence of SISFCL on transmission line fault characteristics and protection, we propose preliminary countermeasures.