The plastic anisotropy of metallic materials originates from the directional nature of the deformation mechanism and the crystallographic orientation distribution of the grains. With the increasing of the complication of the microstructure, e.g. from single crystal to multi-phase steels, the anisotropic behaviour becomes an object with multiple variables, which challenges a clear identification of influencing parameters on the microstructural level using analysis data from only one scale. Therefore, in this study, we show a systematic and multiscale study on the anisotropic behaviour from single crystals to a polycrystal single-phase and dual-phase steel using both experimental and numerical methods. For single crystals, nanoindentation tests are performed to characterise the plastic anisotropy for selective grain orientations, while for the polycrystals, typical tensile tests are used for various deformation directions. An integrated multiscale modelling approach is developed to simulate the anisotropic behaviour of these levels. Within the approach, a fine-resolution construction method of a representative synthetic model allowing consideration of the relevant material features is established with a quantitative evaluation criterion for the representativeness of the virtual microstructure. At the same time, a scheme bridging the equivalent quantities from microstructure to various anisotropic representations of the mechanical behaviour is performed across the single crystal and polycrystals with single or dual-phase configurations. It is demonstrated that with the proposed integrated material modelling approach a uniform solution is found to represent the anisotropy of metallic steels at different levels, which could guide the parameter identification and material design at different scales.