This paper aims to meet the demand for miniaturized, low-cost avionics systems in general aviation aircraft. By analyzing the characteristics and requirements of such systems, it proposes an overall design architecture and details key technologies. These include integrated display and control processing, integrated atmospheric and attitude functions, ADS-B and transponder design, SOC-based data processing and graphics display, microkernel-based avionics software integration, and multi-dimensional situational awareness using aviation databases and multi-sensors. The result is an airworthy avionics system that meets functional and performance requirements while significantly reducing weight, power consumption and cost, showing great market potential.