The linear region of the side-slip mechanical properties of tires is often used in the simulation of linear monorail models for vehicles, especially in the design of active control systems. Side-slip stiffness is a key parameter in tire side-slip, and is significantly influenced by camber and load. In response to the tire industry's need for efficient acquisition of tire mechanical properties and the development of virtual prototyping technology, this paper proposes a method to address the influence mechanism of camber on side-slip in the study of tire camber side-slip prediction models. This paper analyzes the impact of camber on the linear region of tire side-slip mechanical properties at the microscopic level. It then examines the effect of camber on the side-slip condition from the perspective of tire external characteristics, combined with the tire theoretical model, to map the local characteristics of camber onto the external characteristics of tire side-slip. First, a finite element (FE) model of the tire is established based on the tire design parameters, and the accuracy of the model is verified. Three indices — load proportion, load utilization rate, and side-slip stiffness contribution rate — are proposed, and the effect of camber on side-slip stiffness is simulated and quantitatively analyzed. Next, a theoretical model of camber side-slip, considering the complex deformation of the carcass and tire width, is developed. The parameters of this theoretical model are calibrated based on FE simulation results, and the influence of camber on the linear region of side-slip is studied through four different theoretical models. Finally, the influence mechanism of load on the side-slip linear region is investigated using experimental data, FE simulation, and theoretical model calculations. By combining various technical approaches, this paper achieves a mapping of the influence of camber on the microscopic level of tire side-slip to the results of the external characteristics of tire camber side-slip. It also explains why side-slip stiffness decreases with an increase in camber. Additionally, by considering the significant load transfer in the contact patch caused by camber, the study explores the impact of load on the camber side-slip linear region. The conclusion is that the nonlinear changes in tread and carcass stiffness with load are the reason why side-slip stiffness first increases and then decreases with the increase of load. The research results provide a theoretical basis for future high-precision tire model research, tire mechanical property estimation in virtual prototyping, and the development of tire camber side-slip prediction models.