Abstract: A design scheme of mine-used feed switch based on double-controller was introduced. The feed switch is designed with double-controller of single-chip microcomputer and DSP, so as to separate data collection with fault judgment, which improves running speed and intelligence level. And the feed switch has functions of overload protection、open-phase protection、short circuit protection、unbalance protection、leakage locking protection、leakage protection and selective leakage protection. The test result showed that the feed switch has stable performance, quick running speed and high precision.