The influnces of adding AL Mo and Zr elements on corrosion resistance of Ti-Ta alloy in boiling 40% nitric acid solution, and the effect of Ru3+adding into the solution on the alloys have been researched by immersion tests and electrochemistry method.The results show that the corrosion resistances of the alloys are reduced slightly after adding Al and Mo elements in Ti-Ta alloy,and the corrosion resistance is increased by adding Zr.The passivations of all researched alloys are promoted by R3+in solution,and the corrosion resistances of the alloys are increased.The results of elechro-chemical means agree completely with corrosion test.