The invention relates to a power electronic electrical energy conversion circuit, and aims at providing a current source input type resonance soft switching DC/DC converter. The current source input type resonance soft switching DC/DC converter comprises an input voltage source, a transformer, an input inductor, a resonance capacitor and a resonance inductor. A secondary rectifier structure of the transformer is a double-end rectifier structure or a single-end rectifier structure, the resonance inductor and a primary winding are connected into a same branch circuit in series, the resonance capacitor is located on the direct current side of the input end of the transformer, the input inductor is arranged between the resonance capacitor and the input voltage source to serve as a current source, and resonance of the resonance capacitor and the resonance inductor is used for achieving zero-current soft switching. According to the current source input type resonance soft switching DC/DC converter, due to the fact that the soft switching parallel resonance technology is adopted at the input end, power switch tubes work in the zero-voltage turn-on state and the quasi zero-current turn-off state, the overlapping time between the voltage across the two ends of the power switch tubes and currents passing through the power switch tubes is shortened, switching losses of the power switch tubes are reduced, energy on a parasitic inductor or a parasitic capacitor is recycled, and the energy conversion efficiency is improved.