According to the large amount of calculation of high data volume and high requirement of instantaneity of the power quality detection device, this paper designs a power quality detection device base on DSP+ARM dual-core system and AD7606. The device takes advantage of dual-core of DSP+ARM dual-core system and achieve high speed of accessing data, which is high integration and at low cost. The device designed is suitable for development of industrial products with high market competitiveness.