Abstract: The synthesis of MSU-X below pH 3 using sodium silicate solution as silica source has rarely been reported. In the present work, the range of pH value has been extended to about 0.78. Mesoporous MSU-1 silica has been readily synthesized from inexpensive sodium silicate solution and commercial non-ionic surfactant (AEO-9) by the so-called two-step method. Firstly, the inorganic precursor and nonionic surfactant solution at the metastable state (pH2～pH3, t=2 ℃) were assembled and then the silica polycondensation was induced by adjusting pH of the reaction solution (pH0.78～3.94). The products exhibit narrow pore distribution, enhanced short-range order mesoporous structure and micrometric particles- The sample prepared at pH 1.98 has the thinnest pore wall, the largest specific surface area and pore volume, while that synthesized at pH 0.78 has the thickest pore wall, the largest pore diameter and d100 value. The pore wall thickness of products decreases at first and then increases with pH increrase.