The extraction of valuable elements from blast furnace slag by using the acid method suffers from the problem of high silicon concentration in the acid solution，which is not conducive to subsequent filtration and further enrichment of metallic elements，so desilication operations are required.For the problem of desilication from solution，an experimental method of silicic acid self-polymerization-centrifugal desilication was proposed based on the principle of silicic acid self-polymerization，which avoided the problem of easy introduction of impurities by precipitation method and was suitable for the removal of high concentration of silicon under acidic environment.The effects of different experimental conditions on the desilication rate were investigated.The composition of the desilication solution was analyzed by inductively coupled plasma optical emission spectroscopy（ICP-OES），and the crystal structure and microscopic morphology of centrifugal silica slag were analyzed by X-ray diffraction analysis（XRD） and scanning electron microscopy-energy dispersive specterometer（SEM-EDS），while fourier transform infrared spectroscopy（FT-IR） and nuclear magnetic resonance spectroscopy（NMR） were used to study the silicic acid polymerization process.It was found that the optimum process conditions for desilication were：c（H⁺） of 3.5 mol/L，reaction temperature of 70 ℃，holding time of 2 h，centrifugal speed of 3 500 r/min and centrifugal time of 3 min，and the desilication rate of 99.5% was achieved under these conditions.