Intelligent water meter provides an important support for water supply companies to grasp the situation of water users and solve the difficulty of meter reading. However, the traditional photoelectric direct reading intelligent water meter has many problems, such as high power consumption, complex circuit, huge volume, poor long-term stability and so on. Through the research and analysis of the key technology of water meter, a design scheme of water meter based on three-dimensional matrix circuit reading wheel code plate is put forward. It adopts the design idea of separated Mbus communication circuit with STM8L051 ultra-low power consumption single chip microcomputer as the control core, which effectively solves the problems of high power consumption and long-term stability of intelligent water meter. The intelligent water meter is miniaturized. The experimental data show that the optoelectronic direct reading intelligent water meter designed according to the three-dimensional matrix circuit has stable communication, low power consumption, high acquisition efficiency and long-term stability and reliability.