In this paper, we introduce a novel high-radix binary signed digit (BSD) serial-parallel multiplier suitable for low-power high-speed multiplication. The proposed N- bittimesN-bit radix-16 serial-parallel multiplier can reduce the number of accumulation cycles of partial products to as much as N/4, and eliminate most of the invertion operations which consume power in a conventional multiplier in generating the partial products. Unlike other high-radix methods, the pre-multiplication in the new algorithm employs a BSD method which requires no extra adder, and thus removes the extra delay for additions which hinders other high-radix algorithms.