Based on introduction of the isolated analog signal transmission, this paper made analysis and comparison of a variety of isolated technologies, and put forward a novel digital isolating method based on serial interface D/ A converter. 针对系统在不同模块之间信号隔离传输的问题,对各种模拟信号传输的方式进行了性能比较,研究了模拟/数字式变换传输的方式的各种应用。