Because martensitic transformation in titanium alloy significantly affects properties and applications of the alloys, the analysis of the effect of alloy elements on martensitic transformation becomes primarily important. Through using the valence electron structure parameters calculated by the empirical electron theory (EET) of solids and molecules, our analysis results reveal that the addition of alloy elements (such as Zr, Nb, W, Mo, V) has the beneficial effect on the formation of orthorhombic martensite alpha '' as well as the addition of alloy elements (e.g., Al, Fe, Cr, Sn) has advantage to the formation of hcp-structured martensite alpha'. Our analysis results not only present the understanding about the effect of alloy elements on martensitic transformation at the electron structure level, but also provide a theoretical basis for the chemical composition design of titanium alloys. (C) 2010 Elsevier B.V. All rights reserved.