In this study, a quenched Cu-Cr-Ni high-strength weathering steel was investigated. The effects of tempering temperature on its microstructure, strength-toughness balance, and precipitates were examined via optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), combined with tensile tests, low-temperature impact tests, and other characterization methods. The results showed that as the tempering temperature increased from 500℃ to 600℃, the microstructure of the experimental steel transformed from lath-shaped tempered sorbite to non-lath morphology. The fraction of rod-like cementite decreased, while that of spheroidized cementite increased, and the size of MC (M=Ti, Nb, V, Mo) precipitates became smaller. Consequently, the yield strength and tensile strength decreased from 935 MPa and 958 MPa to 866 MPa and 888 MPa, respectively, whereas the impact energy at -40℃ and total elongation increased continuously, reaching their maximum values of 280 J and 5.0% at 600℃. When tempered at 550℃, the experimental steel exhibited a yield strength of 895 MPa, a tensile strength of 921 MPa, an elongation of 4.3%, and an impact energy of 271 J at -40℃, demonstrating an comparatively good combination of strength and toughness. This improvement is mainly attributed to the spheroidization of cementite and the uniformly dispersed fine MC precipitates, which alleviate stress concentration. In addition, the tempering-induced softening of the acicular ferrite (α) matrix contributes to the enhanced toughness.