To avoid the current imbalance among the bridge rectifiers and further suppress the current harmonics in the input side of the parallel 12-pulse rectifier, a 9-phase isolated phase-shifting transformer (IPST) with structure of symmetrical windings is proposed and a novel 18-pulse rectifier is obtained in this paper. Firstly, the voltage phasor diagram of the 9-phase IPST is analyzed, and the principle of phase-shifting of the 9-phase IPST is clarified. Secondly, the input and output characteristics of the 18-pulse rectifier based on the 9-phase IPST are analyzed. The analysis results shows that the proposed 18-pulse rectifier can basically eliminate the 5th, 7th, 11th, and 13th current harmonics of the input side of the rectifier, and reduce the input current THD to 6.7%. Then, the equivalent capacity of the 9-phase IPST is calculated. Finally, an experimental prototype with the output power of 2.5 kW is provided to verify the theoretical analysis.