Biphasic calcium phosphate (BCP) ceramic is commonly used in the biomedical applications particularly as a bone substitute due to its biocompatibility and directly bond to bones. However, the mechanical strength is quite poor. Therefore, well known biocompatible and strong ceramics such as SiO2, ZrO2 and TiO2 were added to improve the strength of BCP. BCP powder with HA/TCP ratios of 70/30 (HAP7030) was obtained by controlling the calcining temperature of the mixture between a pure HA and TCP. SiO2, ZrO2 and TiO2 powder with 2, 5 and 10 %wt were mixed with the HAP7030 powder by ball milling in ethanol. The mixtures were dried, pressed and sintered at 1100°C for 2 hrs. XRD and SEM were used to determine crystal structures and morphology of the sintered samples, respectively. Physical properties and flexural strength of samples were measured. Results showed that the bending strength of HAP7030 sample was rather improved by adding TiO2 than the addition of SiO2 or ZrO2. With increasing TiO2, HAP7030 strength was superior and HAP7030 with 10 %wt of TiO2 obtained the optimum bending strength around 61 MPa. However, the addition of TiO2 induced the thermal stability of HA/TCP, in which HA completely decomposed to β-TCP in this study.