The invention discloses a preparation method of silicon dioxide plural gel and a three-dimensional porous silicon anode material utilizing the same. The preparation method of silicon dioxide plural gel includes (1) mixing a silicon source, a hydrolytic accelerating agent and divalent metal salt solution to prepare precursor solution; (2), subjecting the precursor solution to solvothermal reactionat a certain temperature for a certain time to obtain silicon dioxide plural gel with different compositions and structures. Preparation of the three-dimensional porous silicon anode material includes(1), mixing silicon dioxide plural gel with a reducing agent, namely magnesium powder and a heat absorbent, namely inorganic salt, and performing magnesium thermal reduction reaction in inert atmosphere to obtain magnesium thermal reaction products containing impurity such as magnesium oxide; (2), washing with acid solution to obtain the porous silicon material with regular shape. The preparationmethod is simple without generation of waste liquid of hydrofluoric acid and is easy to realize scale production; the porous material has good cycling stability and rate capability, and has good application prospect.