This research investigated the shear force of dissimilar welding processes between Ti-4V-6Al titanium alloys and Al5052 aluminium alloy by friction stir spot welding (FSSW). The Taguchi L9 orthogonal was used in the experimental design. The welding process parameters are rotation speed (A), feeds (B), and dwell time (C). ANOVA analyzed the S/N ratio of shear force to determine the optimal parameters for statistically significant factors. In addition, analyze for process parameters on the response and the level of the indispensability factor, as well as predict and regression model for optimal tensile strength. The investigation revealed that the optimum parameters were A2B2C3, and the shear force was 2.84 kN. Furthermore, the experiment found that rotation speed and dwell time significantly on the shear force since both factors had a P-value of less than 0.05 (p ≤ 0.05). Therefore, rotation speed and dwell time parameters are the most critical parameters in the process at a 95% confidence level. On the other hand, an investigation of feeds demonstrates an insignificant shear force of the weld due to a P-value above 0.05 (p ≥ 0.05).