The invention discloses a method for preparing 
silicon hollow nano-spheres by the aid of a 
reducing agent which is 
secretion of microbial cells. The method includes steps of (1), inoculating 
saccharomyces cerevisiae, 
brevibacterium flavum, 
escherichia coli, asperigillus flavus, 
pseudomonas aeruginosa or 
aspergillus fumigatus in YPD (
yeast peptone dextrose) culture media, LB (luria bertani) culture media, CA (
cellulose acetate) culture media or 
potato dextrose agar culture media, cultivating the 
saccharomyces cerevisiae, the 
brevibacterium flavum, the 
escherichia coli, the asperigillus flavus, the 
pseudomonas aeruginosa or the 
aspergillus fumigatus in the culture media for 12h-14d and centrifugally removing the cells to obtain 
secretion of the cells; (2), adding the 
secretion of the cells into K<2>SiF<6> or Na<2>SiO<3>, shaking the secretion in a shaking 
bed at the constant temperature of 20-37 DEG C for 16-72h at the shaking speed of 100-300r / min, centrifugally collecting bottom precipitates, and washing and 
drying the precipitates to obtain the 
silicon hollow nano-spheres with the average particle sizes of 200nm. The secretion of the cells is a supernatant. The 
molar concentration of the K<2>SiF<6> or the Na<2>SiO<3> is 0.011mol / L. The method has a series of advantages of environmental friendliness, simplicity in operation, economic efficiency, good 
biocompatibility and the like.