Based on the virtual joint method, the static stiffness matrix model of a 3T1R hybrid manipulator was established considering the elastic deformation of driving joints, ball screw pair, linear guide rail and moving bar. The elasticity deformation of the component was described as one multi-degree of freedom virtual joint at the end of the component, and the branch was then equivalent to a series of rigid components connected by active joint, passive joints and virtual joints. The mapping of kinematic joint and virtual joint variables to the end platform of the mechanism was given. The static equilibrium equation of the manipulator was obtained by using the virtual work principle, and the stiffness matrix model of the manipulator under external load was derived. The evaluation indices of local linear/angular stiffness and global linear/angular stiffness were defined by the dimensionless transformation method, and the static stiffness performance of the hybrid manipulator at the typical configurations as well as throughout the workspace was analyzed accordingly, and the accuracy of the stiffness model was verified by finite element simulation. The results showed that the semi-analytical stiffness model had good accuracy. The z-direction linear stiffness of the mechanism was symmetrically distributed in the workspace. The linear stiffness of the mechanism in the x(y)-direction was decoupled. Linear stiffness of mechanism was much larger than angular stiffness. The research results can provide a theoretical basis for the engineering design and application of the institute.