A porous and fluffy Si@C‐network electrode, in which the Si nanoparticles contact with the carbon conductive network, is prepared by an in‐situ carbonization method on a copper collector. Si nanoparticles are uniformly embedded in the 3‐dimensional fluffy carbon network, which could suppress the capacity decay resulting from the Si volume expansion during the cycling process. The Si@C‐network electrode with a high ratio (83.4 wt %) of active Si exhibits long‐term cycling stability (capacity retention of 765 mAh g−1 after 700 cycles at 2100 mA g−1) and good rate performance. The superior electrochemical performance is attributed to the continuous conductive network, which improves the conductivity of electrode and maintains the electrode structure well after 100 cycles.