In this paper, virtual instrument is used as a development tool to explore the path of accurate monitoring and data processing of signals in a weak environment. Based on the dynamic characteristics of the frequency of the received signal to generate the local carrier and spread spectrum sequence, frequency mixing, code sequence matching received signals, match the results of multi-bit non-coherent cumulative to improve the capture sensitivity, proposed multi-bit cumulative dynamic code sequence matching method. And based on the weak environmental signal monitoring needs, using sample point screening for weak signal digital averaging, improve the signal-to-noise ratio of the target signal, build a weak environmental signal monitoring system. The overall root mean square error of the weak environmental signal monitoring system after incorporating the highly dynamic spread spectrum signal capture scheme remains within the interval of (0.05,0.1) in 50 experiments, which is both stable and effective.