Regular hydroxyapatite nanorods were synthesized using polyethylene glycol as chemical additive and determined by Fourier transform infrared spectrometer, X-ray diffraction and transmission electron microscope. The results showed that irregular quadrate polyethylene glycol/hydroxyapatite complex had formed in the aqueous solution, then hydroxyapatite nanorods with the diameter of about 10-15 nm and the length of 30-50 nm were obtained after calcining. The optimum calcining temperature was 500 degrees C. Nucleation and growth mechanism of the hydroxyapatite nanorods was illustrated. In addition, the stability of the HAP nanorod in the aqueous suspended solution was also considered. The addition of dispersant such as sodium chloride, kalium chloride and sodium dodecyl sulfonate was helpful for the stability of suspended hydroxyapatite nanorod and the mechanism was discussed. Dextran/hydroxyapatite complex with homogeneous size distribution was synthesized, and significant improvements in the mechanical properties were obtained for sintered specimens of the dextran/hydroxyapatite complex in comparison to pure HAP.