Aiming at the power supply requirements of communication equipment and automated instrumentation in modern marine applications, a totem-pole bridgeless Boost PFC converter based on Gallium Nitride (GaN) power devices is proposed. To address the high turn-on losses of rectifier switches when operating in Critical Conduction Mode (CRM) under light-load conditions, Triangular Current Mode (TCM) is introduced as a replacement for CRM to reduce such losses. However, the negative inductor current inherent in TCM causes input current waveform distortion. To mitigate this issue, an input current Total Harmonic Distortion (THD) compensation strategy is proposed to reduce the input current THD under TCM. The on-time expression of rectifier diodes under TCM is redefined to compensate for the inductor negative current introduced by TCM. In addition, extra compensation for dead-time is implemented by plotting the state-plane trajectory curve, so as to reduce the input current THD value under TCM, improve the power factor, and enhance the sinusoidality of the input current waveform. Both simulation and experimental results validate the effectiveness of the proposed input current THD compensation strategy.