The lanthanum-silver doped hydroxyapatite (La/Ag/HAP) powder was prepared by a coprecipitation way. Its microstructure, phase composition and thermostability were investigated by means of X-Ray diffraction, scanning electron microscopy, and Fourier Transform Infrared. The antibacterial properties against E.coli and S.Aureus were detected using a minimum inhibitory concentration method. The biocompatibility was confirmed by cell culture of osteoblasts of rat cranium. Results show that the investigated La/Ag/HAP powder exhibited the features of typical HAP phase in the experimental temperature, and its shape was needle-like with a diameter of 50~80 nm and a length of 300~500 nm. It is of a good biocompatibility and is more stable at high temperature, and is also a stronger antibacterial agent than pure HAP powders.