Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) has the advantage of effective separation of spectral interference. Based on ICP-MS/MS technology, a method for the determination of ultra-trace levels of titanium in bearing steel was established by investigating the effects of spectral interference elimination in different collision/reaction modes (no gas, He, H2, and O2 modes). The spectral interference from Mo++ plasma on Ti+ was eliminated using the O2 mass-shift mode. Considering the signal intensity and signal-to-background ratio of the element to be measured, the optimal O2 flow rate was determined to be 15%. 45Sc was used as an internal standard to correct the influence of instrument fluctuations, and matrix interference was eliminated using the standard addition method. Under optimized conditions, a calibration curve for titanium was established. The mass fraction was in the range of 0.0001%–0.010%, the linear correlation coefficient was greater than 0.999, and the limit of detection values of the four isotopes ranged from 0.00001% to 0.00003%. The relative standard deviation (RSD) was less than 5.0% when steel samples with three additive levels were measured six times. The recovery of titanium ranged from 90.0% to 120.0%. This method is simple to use, easy to popularize, and meets the requirements for daily analysis. In addition, the critical value of titanium in high-quality bearing steel was evaluated by calculating the uncertainty.