MS nanoparticles were prepared with chitosan (CS) as the synthesis template at normal temperature by simulating biomineralization method. ZnS-, PbS-, and CdS-CS nanocomposites as model were prepared by simulating biomineralization method of corresponding twain valent ions into nanoparticles in the presence of CS. The structural and morphological features of MS (M = Zn, Cd, and Pb)-CS were investigated by scanning electron microscopy. Optical characteristics of nanocomposites were studied by the approaches of ultraviolet-visible spectroscopy and fluorescence, from which the conclusions show that the CS matrix offers limited conditions for ZnS to grow, the precursor concentration can also affect the formed particle size, and thus the particle size can be controlled in the CS matrix by these two means. The differential scanning calorimetery result indicated a strong and uniform interaction between CS and nanoparticles. The experimental results indicated that all the nanoparticles aggregated into nanopartical and CS as a template played an important role in the formation of nanopartical. In addition, a possible structure-controlling mechanism was proposed. (C) 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 269-275, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20222