This paper proposes a structure of peak current mode Boost DC-DC converter with slope compensation circuit, and designs a dynamic slope compensation circuit applied to this converter. With the utilization of the voltage controlled resistance characteristics of MOS transistor and the introduction of a clamp circuit consist of cascade current mirror, a dynamic slope compensation circuit is realized. The circuit is simulated on Cadence Spectre using SMIC 0.18μm CMOS technology. Results show that it can provide proper slope compensation following the variation of input and output. The load capacity of DC-DC converter reaches 550mA and the transient response lows to 10 μs. By eliminating the problem of instability caused by the peak current mode switching power supply of double loop control, the design improves the stability of switching power supply.