A)Is there any ways to increase the icons size of the buttons in the deformation subpalette? the axis buttons are somehow smalls.
B)And, Is there any ways to disable the shading variation that occurs when selecting subtools?
thanx 
For B: fill the subtools with the same color and material.
no, even when they are the same there is a slight shading variation between a selected subtool and the others.
I want to know how to get rid of that.(not all materials but a lot shows the selected subtool lighter)
But thanx anyway
I can`t see any difference after I fill all the subtools with the same color and mat.
The easiest way to fill all the SubTools with the same color and material is to use SubTool Master. It has an option to fill all visible SubTools with a single click. And yes, this will prevent any shading variation caused by selecting SubTools. (FYI, there is a difference between simply selecting a color/material and actually filling the object with it.)
For your other question, the only way to enlarge those XYZ indicators is to enlarge the interface elements. Preferences>Interface>Button Size will do this. Set a larger value, then press Ctrl+Shift+D to save the setting. Restart ZBrush.