Chemical durability of selected compositions in RO Al 2O 3 P 2O 5(RAP) glass system(R=Zn,Mg) in deionic water and simulated physiologic solution were measured respectively. The measurements showed that the corrosion mechanism of RAP glass is quite different from that of Na 2O CaO SiO 2 P 2O 5 bioglass.The results from infrared spectrum experiments have confirmed the existence of PO 3 and P 2O 7 groups,as well as the stable Al(PO 3) group in the structure of RAP glass.