I've been playing always making str and dex high for high damage but I heard It does't affect anything for Santier Spear, is that correct?
I feel stupid it thats true
please help.
You are correct.
http://darksouls2.wiki.fextralife.com/Santiers+Spear
If you scroll down halfway and look at the various upgrade paths, you will notice it has no rating for Strength nor Dexterity, meaning it will receive zero bonus from either of those stats.
Compare it with a simple dagger and you'll see the basic dagger gains E and B on Str and Dex scaling respectively.
You can easily tell what stats any equipment is based on:
At the bottom of the inventory page, you can see the requirements each piece of equipment requires, and the scaling that it might have.
From left to right: STR, DEX, INT, FAI
The top row (yellow icons) shows the level of requirement, whereas the second row (green row) shows the additional scaling it might provide. This example suggests:
So, as suspected; no. The Santier's Spear (Un-enchanted) does not gain any bonuses from any of your stats.