Colloidal gold was reductively prepared by sodium citrate, sodium citrate-tannin, ascorbic acid and sodium borohydride respectively. And corresponding gold particles size, morphology, dispersion, and stability of the samples were characterized and compared. The results showed that the colloidal gold particles via sodium citrate-tannin reduction method possessed a diameter range of ca. 10 nm, and demonstrated narrow size distribution, uniform morphology, good time-dependent stability and dispersion. This colloidal gold could be used to biomarkers directly. Furthermore, this method has obvious advantages over other three above-mentioned methods.