Aiming at the problems of high failure rate, low power density, and poor economy in parallel configuration of multiple independent DC-DC converters in power generation systems containing new energy, an intensive high-gain three-port DC-DC circuit is designed. The converter is respectively connected to the power supply unit, the energy storage unit and the load, and can realize energy flow to any two ports. The secondary boost circuit is used to obtain a high-gain voltage output. First, analyze the principle of the three working states of the proposed three-port converter, then calculate the voltage gain of the converter and the stress of the switching device. Finally, an experimental prototype with a power of 200W was built to simulate and verify the theoretical analysis, the experimental result is that when the input voltage is 25V, the inverter can get an output voltage of 120V in three working modes. The charging current of the energy storage battery is 3A and the discharging current is 4A. The experimental results show that In the new energy power generation system connected to the energy storage unit, the converter can ensure stable and high-gain voltage output.