This invention related to a high carbon and high molybdenum/tungsten martenisitic type iron base alloy with excellent hot hardness and wear resistance for making valve seat insert. The alloy comprises of 2.05-3.60 wt % carbon, 0.1-3.0 wt % silicon, 0-2.0 wt % manganese, 3.0-10.0 wt % chromium, 11.0-25.0 wt % molybdenum and tungsten, 0.1-6.5 wt % nickel, 0-8.0 wt % vanadium, 0-6.0 wt % niobium, 0-8.0 wt % cobalt, and the balance being iron with impurities.