Cloud web of audio noisedetection providesthe local polluted information and send thenoise values and their distribution to the sever in cloud web center or other websites. It serves Environmental Protection Authority for noise monitoring in digital and intelligent ways. Bottom layer of the web, namely physical layer, is the noise detection digital probe and is one of the major techniques. The paper describes a DSP5509 based digital noise measurement research, in which IIR filter is developed to make A or C weighting. Zigbee protocol WSN interface is embedded to realize information interconnection. Experiments show the probe can timely detect the audio noise signal within 20~20kHz in frequency and 40~100dB in amplitude. Absolute error is controlled less than ±1dB.