Fe-Cr based damping alloys have high mechanical properties and good corrosion resistance, which have been applied to reduce vibration and noise. Their high damping behavior is primarily attributed to the stress-induced irreversible movement of 90° magnetic domain walls. Most researches mainly focused on the damping behavior of these alloys. However, little attention has been paid to the mechanical properties, which are the important consideration for engineering applications. Recently, a FeCrMo damping alloy with Cu addition was found to possess higher damping capacity and higher mechanical properties. In this work, scanning transmission electron microscopy (STEM) and dynamic mechanical analyzer (DMA) were used to investigate the Cu precipitation and its influences on damping capacity and mechanical properties of FeCrMoCu alloy (1.0% and 2.0% Cu addition, mass fraction) with dif ferent cooling rates. The results show that the Cu element in 1.0Cu alloy is fully dissolved in the matrix. When the cooling rate is slow (furnace cooling), there will precipitate a small amount of second phases, which are small in size (<5 nm) and contain relatively few Cu atoms (3.7%). As for 2.0Cu alloy, with decreasing cooling rate (from water cooling to air cooling, and to furnace cooling) there will firstly precipitate a small amount of second phase with small size (<5 nm); subsequently, the particles grow into a spherical shape (10~15 nm) and their number increases; at last, the particles transform into round bar with coarse size of 100~400 nm and the precipitate number decreases obviously. The Cu content of the latter two precipitates increased obviously (about 30%~40%). These precipitates will significantly increase the average internal stress of the experimental FeCrMoCu alloy, which will obviously decrease the damping capacity. Therefore, the damping capacity of 2.0Cu alloy is much lower than that of 1.0Cu alloy. Meanwhile, the precipitate will obviously improve the strength. Compared with coarsen Cu-riched phase, the finer second phase has better hardening effect and its influence on ductility and toughness is relatively small. The FeCrMoCu alloy with addition of 1.0% Cu can obtain better damping capacity and mechanical properties at the same time.