The microstructure evolution of laser multi-layer deposited Ti-XAl-YV (X￡11, Y￡10, mass fraction, %, similarly hereinafter) alloys from blended elemental powders with the content of Al and V was studied. Results show that the size and quantity of a colony in the prior b grains are decreased gradually with the increase of Al and V, and the microstructure in prior b grains changes from widmanst?tten structure to basketweave structure with the a laths and b phase braided. Meanwhile, the size and aspect ratio of a laths are decreased obviously. The nucleation and growth conditions of a phase in single-line laser multi-layer deposited Ti-XAl-YV alloys were analyzed and the microstructure evolution mechanism was revealed on the basis of thermal history modeling, a→b transformation temperature computation and the phase diagram analysis of Ti-XAl-YV alloys.