Si release and structure changes of three phyllosillicates (kaolinite, montmorillonite, illite) were investigated after being batch cultivated by two kinds of organic acid (oxalic acid and citric acid) under different concentrations (0 - 0.500 mol/L) at 25℃. Results indicated that with the increase of time Si release from kaolinite and illite reached the maximum amount after cultivation by organic acid under different concentrations for 15d. The release amount of Si from phyllosillicates in organic acid was between 0.48 and 244.30 μg/ml (SiO2) and higher in oxalic acid treatment than that in citric acid. Si release from each phyllosillicate decreased with the increase of organic acid concentration. The release amount of Si was most from montmorillonite compared with other phyllosillicates with the same concentration of organic acids. With the increase of organic acid concentration, the characteristic peak intensities of montmorillonite in X-ray diffraction (XRD) pattern decreased successively and more remarkable in oxalic acid treatment than in citric acid, while there were no obvious changes in cultivated kaolinite and illite.