This work investigates the influence of the pre-existing He bubble on the crack propagation in TiT1.75 with molecular dynamic simulations. Under high strain rate tension, TiT1.75 exhibits typical brittle fracture characteristics with low fracture toughness at the microscopic scale, and the crack propagation path approximately follows the (111) plane with normal stretching direction. However, the presence of He bubble may change the stress concentration near the crack tip, resulting in the bending and even branching of cracks. The position relationship between He bubbles and crack tips is discussed, and the results show that He bubbles can improve the tensile strength and fracture strain within a certain distance and angle range. The total length and pattern of crack propagation are also presented. Note that, the tensile strength will decrease as the bubble density increases to a certain extent, for the self-expansion and coalescence of He bubbles will dominate the fracture process.