A method for collecting communication information, a test method and a network device are disclosed. The method for collecting communication information includes: presetting a command for collecting diagnostic information about voice quality, and obtaining Dual Tone Multi Frequency (DTMF) signals; and judging whether the DTMF signals match a preset command for collecting diagnostic information about voice quality, and collecting information according to the preset command if determining that the DTMF signals match the preset command. A test method is also provided, and, accordingly, a network device is provided. Through the technical solution under the present invention, diagnostic information is collected quickly after a voice quality problem occurs.