Amount of water soluble protein was observed through modified lowry method. It was found that the water soluble protein contented after incubation the HA-NR latex with urea was reduced from 4,245 Pg/g to 15 Pg/g. DPNR composite was prepared by incorporated nano-calcium carbonate (Nano-CaCO3) at 1 - 4 wt% into pre-vulcanized DPNR latex. Then, physical properties of the DPNR latex were investigated. The thermal properties of DPNR was investigated through the dynamic mechanical thermal analyzer and oxidation thermal aging. It was found that the corporation of nano-CaCO3 in DPNR latex could improve thermal and mechanical properties of the rubber. The results showed that the loss tangent (tanG) was found to shift to lower temperature.