To achieve high strength and good electrical conductivity, thermo-mechanical treatments are usually applied for precipitation strengthened Cu–Cr–Zr alloys. However, the dislocation-precipitate interaction is still unclear for these alloys during deformation and post-aging, which hinders a further improvement in their mechanical-electrical properties. In the present study, to investigate the effect of precipitates’ size and their orientation relationship with the Cu matrix on the dislocation accumulation during rolling and post-aging, a thermo-mechanical treatment was fulfilled by adjusting the pre-aging state of the alloys. Samples with four precipitate states (solid solute, under-aged, peak-aged, and over-aged) were subjected to rolling and post-aging, respectively. The results showed that, the under-aged sample with less precipitates accumulated the similar deformed structure as the peak-aged one during rolling and relieved the negative effect caused by aging recovery during post-aging, retaining more deformed structure. Therefore, the ultimate tensile strength reached to 588 MPa, ∼30 MPa higher than those with other pre-aging treatments. Additionally, the re-dissolution and refinement of precipitates caused the abnormal decrease of electrical conductivity during rolling, and the post-aging treatment restored the electrical conductivity to the normal level (81% IACS). The results indicate that a proper under-aging pre-treatment before rolling helps to obtain better mechanical properties, which is feasible for large-scale industrial production and can be extended to other thermo-mechanical treatment forms.