Which means, an object that circle shaped in modeling file is not printed out as circle as the model is.

See the following images.

This is what it should be.

And this is what i get.

Here's the difference.

I've done several calibrations, but it does not get better.

What you guys think of this problem doodlers?

Have you followed our belt calibration video? This is the most likely culprit.
Second would be stepper motor calibration via the trim pots.

See the following images.

This is what it should be.

And this is what i get.

Here's the difference.

I've done several calibrations, but it does not get better.

What you guys think of this problem doodlers?