This paper conducts an in-depth study on the deformation characteristics of sulfate salted soil in the Qinghai region and proposes an ideal elastoplastic model that considers salt content and confining pressure. Firstly, through the determination of liquid plastic limit and soluble salts, it is indicated that the four typical areas are primarily composed of silty clay and clay, with sulfates being predominant. Original saline soil samples from three sampling points were selected and subjected to artificial salt washing, preparing six soil samples with different mass ratios of sodium sulfate. Secondly, consolidation undrained triaxial tests were conducted under four confining pressures and six salt contents, revealing that the stress-strain relationship of the saline soil exhibits a distinct ideal elastoplastic characteristic: a clear linear segment is visible before yielding, with no significant hardening or softening after yielding. Under the same confining pressure, the initial elastic modulus, yield stress, and shear strength all gradually decrease with increasing salt content; at the same salt content, the initial elastic modulus and yield stress increase with increasing confining pressure. Finally, based on the test phenomena, the constant initial modulus and yield point in the ideal elastoplastic model are considered as functional expressions. By using MATLAB programming analysis and parameter optimization, a model is established where the initial modulus and yield stress are linearly expressed in terms of confining pressure and salt content. This model has fewer parameters and, in addition to reflecting changes in strength, can also describe the influence of salt content and confining pressure on the initial modulus, thus providing a more accurate description of deformation for engineering reference.