The elements for eutectoid and ordering transformation of titanium alloy were summarized in this paper,whose eutectoid characteristic and mechanism was also discussed.It was pointed out that the bonded power(Bo) of alloying elements in titanium alloy would be the key factor of eutectoid characteristic.In the end the important eutectoid elements and their intermediate compound with Ti were presented,respectively.Based on the former paper,this one perfects the solid-state phase transformation theory of titanium alloy further and has some instructional effect on alloy design.