Star and linear block copolymers of [poly(4-vinylpyridine)-block-polystyrene](n) [(P4VP-b-PS)(n)] and [polystyrene-block-poly(4-vinylpyridine)](n) [(PS-b-P4VP)(n)] (n = 1-4) with similar chemical composition but different block sequence were synthesized by RAFT polymerization. Star (P4VP-b-PS)(n) is composed of a jointed P4VP core and several outer PS arms, and (PS-b-P4VP)(n) has just the opposite block sequence and different conformation. The effect of block sequence on the block copolymer nanoassemblies is explored. It is discovered that star (P4VP-b-PS)(n) tends to form complicated nanoassemblies in the block selective solvent for P4VP due to the PS arms bridging, and star (PS-b-P4VP)(n) acts somewhat like linear amphiphilic block copolymers. Our study demonstrates the crucial role of block sequence in star block copolymer nanoassemblies.