Abstract: Stud connectors are widely utilized in steel-concrete composite structures to counteract shear forces at material interfaces. To investigate the influence mechanism of steel fiber reinforced concrete (SFRC) parameters, of loading patterns and, of rubber sleeve parameters on the shear stiffness of stud connector, 18 groups of 54 specimens were studied by a push-out test method. The shear-relative slip relationship curve, failure mode, and shear bearing capacity of the stud connector were obtained, and the calculation method of the shear stiffness of the stud connector and its influencing factors were summarized. The stud connector was regarded as a Euler beam acting in SFRC, and the Winkler hypothesis was satisfied. The shear mechanism analysis model of stud connector was constructed upon the elastic foundation beam theory, and the shear stiffness calculation formula suitable for SFRC rubber-sleeved stud connector was put forward. The results show that rubber-sleeved stud connector can significantly reduce the stud connector shear stiffness without obviously weakening its bearing capacity (less than 15.8%). When the rubber sleeve thickness is from 0.0 mm to 2.5 mm (11.4% of the stud connector diameter) and the rubber sleeve height is from 0 mm to 25 mm (25% of the stud connector height), the shear stiffness of the SFRC rubber-sleeved stud connector decreased by 43.9% and 44.61%, respectively. The shear stiffness of SFRC rubber-sleeved stud connectors is positively correlated with the compressive strength and elastic modulus of SFRC and negatively correlated with the ratio of the rubber sleeve height to the stud connector diameter, showing an approximate exponential change. The shear stiffness of SFRC rubber-sleeved stud connector shows an approximately positive linear correlation with the steel fiber content. The loading patterns do not significantly contribute to the shear stiffness of SFRC rubber-sleeved stud connector. The shear connector stiffness formula for SFRC rubber-sleeved stud shear has an average ratio between the predicted and experimental values of 1.005, and the relative error is less than 15% with the results of related literatures, which serves as a reference for similar projects.