A cochlear implant stimulating circuit was designed. The chip can provide precise stimulus current to the 17 electrodes. The chip also has error detected ability, it can be used for different speech encoding algorithm. The chip is a mixed signal circuit. It was designed and fabricated with 0.35um EEPEOM process. Dual power supplies are used for the chip, one is 12V, and the other is 3.3V. The total area is 9mm2, and the power is less then 10mW. The structure of the whole chip is introduced in the paper. The results of the chip are also described.