EAST tokamak is one of the advanced full superconducting tokamaks in the world. To achieve better plasma parameters, new plasma position and shape are calculated and optimized in the 2013's update. New divertors should be deigned and developed to endure higher heat flux less than 10MW/m2. The divertor is ITER-like structure. It bases on mono-block and cassette technology. The divertor is composed of PFC units, cassettes and support systems. Mono-block structures are just employed on the PFC units of target plates of the divertors, thus W flat tiles are used on the baffles and dome. Cassettes act as not only the supports of the PFC units, but also the cooling channels of the units. The support systems consist of inner support rails, outer support rails and auxiliary braces. The systems are installed on vacuum vessel before cassettes putting on. When cassette assembly with support system, it is just lifted and pushed forward. To optimize and verify the structure, R&D work has done on the divertor. The prototypes of PFC units in different positions and cassettes with different manufacture processes are fabricated. The assembly process is also simulated with these prototypes on mimic facility and vacuum vessel. The results show that the divertor system can be manufactured successfully according to the drawing requirements. And they can also be installed conveniently and precisely on the tokamak. All R&D work and tests will certify that the design of divertor is all right.