High strength (>1000Mpa) and high electrical conductive(>70%IACS) Cu base in-situ composites have been developed. The effects of alloying elements such as Zr, Ti, Sn, Fe, and Si on the mechanical properties as well as electrical conductivity were systematically studied. The best combination is the addition of 0.1-0.2 mass% Zr, Ti, or Sn in Cu-15mass%Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The manufacturing process consists of VIM cast, hot rolling, solution treatment, cold rolling, and aging. Aging at 773K for 1 h after cold rolling for eta=7.0 is most favorable. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of second phase, and the precipitation of mainly fine Cr phase. The aging treatment to reduce solute atoms has beneficial effect on the increase of electrical conductivity.