go to https://wiki.ubuntu.com/X/Config/Input

find Example: Disabling middle-mouse button paste on a scrollwheel mouse header

and follow instruction.

Scrollwheel mice support a middle-button click event when pressing the scrollwheel. This is a great feature, but you may find it irritating. Fortunately it can be disabled.

First, you need to know the id of the mouse, like this:

$ xinput list | grep 'id='

which prints something like

⎡ Virtual core pointer                      id=2    [master pointer  (3)]
⎜ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
⎜ PixArt Dell MS116 USB Optical Mouse       id=12   [slave  pointer  (2)]
⎣ Virtual core keyboard                     id=3    [master keyboard (2)]
  Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]
  Power Button                              id=6    [slave  keyboard (3)]
  Video Bus                                 id=7    [slave  keyboard (3)]
  Power Button                              id=8    [slave  keyboard (3)]
  Sleep Button                              id=9    [slave  keyboard (3)]
  Dell KB216 Wired Keyboard                 id=10   [slave  keyboard (3)]
  Dell KB216 Wired Keyboard                 id=11   [slave  keyboard (3)]
  Eee PC WMI hotkeys                        id=13   [slave  keyboard (3)]

My Dell Usb mouse has printed here for which id=12

so, I can view the my mouse button mapping like:

$ xinput get-button-map 12

which prints

1 2 3 4 5 6 7 8 9 10 11 12

here only the first three numbers have meaning for me. They represent the left, middle, and right mouse buttons.

I can turn the middle mouse button off by setting it to 0:

$ xinput set-button-map 12 1 0 3

Or I can turn the middle-mouse button into a left-mouse button by setting it to 1:

$ xinput set-button-map 12 1 1 3

ref. link https://wiki.ubuntu.com/X/Config/Input