In high power applications, parallel structure is often used to increase the output power of the converter. In LLC resonant converter, a large resonance frequency point offset will be caused due to the subtle difference in resonance parameters of each parallel unit, and it is difficult to achieve output current sharing in parallel. In this paper, the Fundamental Harmonic Analysis (FHA) will be used to analyze two different LLC resonant converter parallel structures. The analysis proves that common capacitor structure can achieve more excellent current sharing characteristics than IPOP structure. Two parallel-structured LLC resonant converter prototypes were built and compared to verify the conclusion.