password query display hex code

When I excute "select password('test')"

This is returned hex string

"0x2A39344244434542453139303833434532413146393539464430324639363443374146344346433239"

heidisql version is 9.5

How Can I fix this error?

This happens because your server incorrectly reports the columns as binary. If I'm not wrong this was fixed several some years ago so upgrading MySQL Server to a recent version should fix the issue (unless it's a recurring bug that comes and go, I can't tell for sure). Alternatively, you can click the "View binary data as text (instead of HEX)" button in HeidiSQL.