Abstract: A design scheme of intelligent soft-starter for three-phase asynchronous motor was introduced. The soft-starter is designed by use of LPC2364 as controlling core and EPM7128SLC84-15 as logic signal process circuit, and can communicate with upper computer through Modbus field bus. The soft-starter can softly start three-phase asynchronous motors with diverse power by multi ways such as torque and realize more than twenty motor protections by real-timely monitoring motor's running parameters. The actual running result showed the soft-starter has stable running, simple operation, high anti-interference performance and convenient extension.