Can I use this 1.8" TFT LCD to make it show graphic? Or all the TFT LCD can display graphic?
Yes, you can draw graphics on this display.
You can draw graphics on any display that is (individually controllable) pixel based, i.e. it mentions a resolution, something like 128 x 160 in the specs. They are referred to as "Graphic" displays. Common types include STN, TFT, OLED.
The other common type of display is usually referred to as "Alphanumeric", and lists a spec like 16 x 2 (characters x lines) With these you can only display letters/numbers.
Most Alphanumeric displays are STN (Super Twisted Nematic) based.