The 21st Century is a highly developed scientific and technological community, there are a wide range of high-tech products, high-tech children toys is one of them. the smart voice dolls such toys also germinate because of it. I designed AT89S51 microcontroller as the core of the doll voice circuit system, it contains power controller voice and display. The whole system integrated in a 9X14cm universal board, each module is reasonable placed. Based on the basic functional requirements, the voice part is on a focus of the design. The prototype is in the basic task of achieving requirements, in addition, the external microcontroller interface is expanded, an adjustable clock module is increased, an external microphone is set up, which allows the user to modify the different voice at different times. The fun of toys is increased, there is some innovation.