In this paper we present the algorithm of a 16-bit hybrid multiplier, which can work in two modes. In normal mode, it performs a 16-bit multi-plication. In SIMD mode, it performs two parallel 8-bit multiplications. The proposed algorithm is based on the raix-4 modified Booth's algorithm. Our algorithm generates ten partial products and a modifier, which is five less than the other algorithms. We can get one 32-bit product or two 16-bit products by directly accumulating the ten partial products and the modifier, easing the design of the tree structures for compressing the partial products and the final adder. The proposed algorithm is adopted by YHFT-DSP/800, a high perfor-mance fixed-point DSP. The multiplier was full custom designed in 0.18um CMOS technology. We also designed a test chip. The test results show the multiplier works well at 400MHz in normal mode, 480MHz in SIMD mode. The simulated power is 35.8 mW at 400MHz, and 42.5 mW at 480MHz.