Ten types of rare earth (RE) compounds modified carbon black (HAF-RE) were prepared using chemical-deposit method, then HAF-RE were mixed with natural rubber latex to prepare HAF-RE filled powdered natural rubber [P(NR/HAF-RE)] by a carbon black/rubber latex coagulation method. It is found that most of the P(NR/HAF-RE) vulcanizates showed better mechanical properties, especially higher tensile modulus, and tensile strength, compared with none-rare earth modified carbon black filled powdered natural rubber [P(NR/HAF)]. Dysprosium (Dy) modified carbon black (HAF-Dy) filled powdered natural rubber [P(NR/HAF-Dy)] was chosen for intensive investigation because of its better comprehensive mechanical properties. It is found that the adding of Dy compounds could help to get smaller particles with narrower particle size distribution, and results from the SEM analysis show that carbon black has been dispersed in rubber matrix uniformly with diameter of 50-150 nm. The TEM analysis showed that Dy compounds could obviously reduce the aggregation of primary particles of carbon black, and promote the dispersion of carbon black in P(NR/HAF-Dy) particles. (c) 2008 Wiley Periodicals, Inc.