Abstract: Copper and copper alloys have excellent electrical and thermal conductivity and are widely used in various fields. In this article, Cu alloys with 0.9wt% Nb, 0.95wt%Nb, 1wt% Nb and 1.5wt% Nb were prepared by using a comprehensive planetary ball mill and microwave mafer furnace. Using scanning electron microscope (SEM), optical microscope (OM), energy dispersion spectrometer (EDS), X-ray diffractor (XRD), conductivity tester, Vickers hardness tester, electron densitometer and other means to explore the changes of copper matrix organization and performance under different Nb content. The results show that at 1000℃, the niobium content is in the range of 0.9% wt-1.5wt%; with the increase of niobium content, the hardness of the niobium content; Nb addition reaches 47.9 HV at 0.95wt%; the conductivity decreases with the increase of niobium content. Fine crystal reinforcement is the main way of strengthening copper niobium composite materials. With the continuous increase of niobium content, copper grains have an obvious trend of refinement. The more obvious the niobium elements distributed at the grain boundary, the stronger the effect of the grain.