Abstract: Aiming at increasingly serious problem of harmonic pollution in power system,the paper introduced design of a new type of embedded harmonic detection device.The device adopts master-slave structure,which takes single-chip microcomputer as main CPU to control running of the whole device and takes DSP as slave CPU to process data,and adopts a new type of harmonic detection algorithm named kalman algorithm,which takes the minimum mean square error as rule and uses state equation and recurrence method to estimate present process state according to the last observed data and the most recent one.The device can detect harmonic in power grid real-timely and reliably and has characteristics of fast operation speed,high precision,simple structure,correspondingly low cost,easy operation and strong display function.The simulation result showed the validity and reliability of the device.