The in-situ Ti alloying of low-Ti Al alloys and their application in A356 alloys were studied. The results show that the currency efficiency is comparable to that of pure Al, which is about 92%. The absorptivity of Ti is over 95%. Such obtained A356 alloys with different Ti content have excellent grain refinement effect and fading resistance comparing with the tradition A356 alloys. The refinement of grain always companies the refinement of Si particles. The strength is comparable to that of the tradition A356 alloys whether the alloys are unmodified or modified with Sr, but the ductility and quality index are superior to that of the tradition A356 alloys. The alloys with 0.1%Ti have the optimal mechanical properties.