Problem to creat mesh 2D
 

I create simple geometry (image 1) and I want to mesh it with 8000 node. I tried many times to create mesh but unfortunately my result is image 3.

What am I doing... Please help me...

I chose curve mesh: Max size=0.01 Height=0.01 and Height Ratio=1.5

I'm waiting! Please help me!

Which mesher are you using? Two things have to be done in ICEM.
first, after setting the curve size, you should associate edge to curve. Or you can set the edge parameters directly.
And you can select a bunching law.

I don't know which one is better. Hexa meshing... could you explain which one is better and some tutorial or explanation how I can do it...

I mention ICEM just because I am using it and explain the steps with this software.
about your case, you can read the tutorial with the software at first to get some points. and this simple case can be solve.

Update Sizes and Edge Params...
 

Yes, try a tutorial or two. It looks like you are using ICEM CFD Hexa.

The 2D pipe (simplest) or 2D car tutorials should sort this out for you.

Both tutorials start with just curves, but as an ICEM CFD Hexa expert, I suggest creating the surface also (put it in your fluid or solid part).

Once you have a surface, you can use it to set the sizes.

Then once in the Hexa Blocking tab, you should update the sizes. This will take the sizes from the geometry and apply them to the blocking. And/Or you can set the size on each edge individually with the edge params.

But yes, as HM Lee says, you must also associate edges with curves. If you don't, your solver will give you errors because you won't have any boundary line elements.

Simon