A sensitivity analysis is performed to determine the key uncertain geometric parameters that influence the mechanical response of a mining dragline joint subjected to large dynamic loading. An alternative design is modeled where the welded of the lacing members are attached on the sleeve structure rather than welded to the main chord directly using ABAQUS. Based on the simulated values, the Sobol's variance-based method which consists of first-order and total-effect sensitivity indices is presented. The sensitivity of four uncertain geometric parameters on the mechanical responses are investigated; i.e. thickness of sleeve, thickness of bracing members, weld fillet and eccentricity. To conclude, it is observed that the thickness of sleeve is the most dominant uncertain geometric parameter with respect to the specified mechanical responses.