Hi Faguo1502,
This particular detection does not mean that the software is malicious, but is instead a Potentially Unwanted Program. This typically means that the software is identified as performing actions that many users find undesirable (for example, software that installs browser toolbars or re-directors, or features excessive pop-ups would classified as a PUP).
If you would like to disable the PUP detections, please open Avast Security > click "Preferences" on the bottom left of the window > click the "Settings" link under File Shield > un-check the "Report potentially unwanted programs (PUP)" option.