In the DCSmicro grid,Sthe converter is a very important unit and it’s significant to study its impedanceScharacteristic and stability. Based the Boost DC/DC converter, the small signal model in continuous conduction mode is derived by different control modes in circuit parameters(inductance, capacitance etc.) respect. And then the output impedanceScharacteristic is analyzed by the combination of math theory and experiments and providesSreference basis for the standard of theSconverter impedance in distributed system of theSmicro grid. Finally, a cascade DC/DC converterSsystem was built to measure the impedance ratio. So the stability of the cascade system is judged by the impedance ratio criterion. The influences of the circuit parameters on the system stability were analyzed and theSregular pattern and conclusion were summarized to analyze the stability of the DC micro grid.