Objective To study the Corrosion fatigue properties of a new low modulus Ti-3Zr-2Sn-3Mo-25Nb (TLM) titanium alloy under the intervention of simulated body fluid. Methods Using Ti-6Al-4V (TC4) titanium alloy as the control group, the electrochemical corrosion polarization curves of two titanium alloys were measured in simulated body fluids. The pre corroded TC4 titanium alloy and TLM titanium alloy samples were subjected to rotational bending fatigue tests, and the loading stress amplitude was established using experimental data（σa) And fatigue fracture cycle (Nf), draw the stress life curve, analyze the fracture mechanism by analyzing the Corrosion fatigue micro fracture morphology of the sample, and conduct fatigue analysis on the titanium alloy sample combined with the finite element software. Results The self corrosion potential (Ecorr) of TC4 titanium alloy under stress annealing is lower than that of TLM titanium alloy after heat treatment, and TLM titanium alloy is more sensitive to changes in cyclic stress. Simulate the fatigue behavior of two titanium alloys using finite element software, and compare the simulation results with the experimental results. Conclusions TC4 titanium alloy under stress annealing has higher fatigue strength and stronger resistance to crack propagation compared to TLM titanium alloy after heat treatment, while its corrosion resistance is the opposite. Compared to the specimens without pre corrosion treatment, the brittleness of TLM titanium alloy increased and its fatigue performance decreased after pre immersion in simulated body fluid. Through comparative analysis, the reliability of the test results is high, and COMSOL finite element software can effectively predict the fatigue life of titanium alloy materials.