Submicron α-tricalcium phosphate (α-TCP), β-tricalcium phosphate (β-TCP) and biphasic α/β-TCP powders were prepared by an amorphous calcium phosphate (ACP) precursor way. For the biphasic TCP powders, primary particle size was 300nm, α-TCP and β-TCP primary particles were homogeneously mixed in the submicron powders. When the TCP powders were soaked in acetate buffer solution with pH 5, the Ca ion concentration in the soaked solutions and the resulting morphology variations were measured and observed. The results showed that the dissolution behavior of the biphasic TCP powders was different from α-TCP and β-TCP, and had a higher dissolved Ca ion concentration. This is attributed to a high supersaturation which is cased by the distribution homogeneity of two phase primary particles in submicron powders. These demonstrate the biphasic TCP to have potential to extend biological applications of Ca phosphates.