Effect of cooling rete on microstructures, hardness and hydrogen permeation properties of V55Ti30Ni15 alloys were investigated in present study. The results indicate that the microstructures of the alloy consist of the V(Ti, Ni) solid solution and the NiTi and NiTi2 compounds. The cooling rate has significant effects on the microstructures and properties of V55Ti30Ni15 alloys. The volume fraction of V(Ti, Ni) solid solution and second dendrite arm width and spacing decrease with increasing in cooling rate. The hardness value increases with increasing cooling rate, but hydrogen permeability decreases. The hydrogen permeability of V55Ti30Ni15 alloy is linear relationship with the volume fraction of V(Ti, Ni) solid solution. The hydrogen permeability is not only relate to the volume fraction of V(Ti, Ni) solid solution but also the content of Ti and Ni and the volume of phase boundaries in V55Ti30Ni15 alloy.