What's the causes of leucocyte at my urine? Is there any test what cause these?

This is, once again, something you need to discuss with your doctor who has your medical records and history and can talk to you face to face to answer your questions. If your doctor won't talk to you, then you may need to find a new one.

You have a urinary tract infection. This should explain it.

Leukocytes in Urine | MD-Health.com (http://www.md-health.com/Leukocytes.html)

Several time I talked with my doctor . He said its normal.

Several time I talked with my doctor . He said its normal.
If you have talked with your doctor why are you asking us? None of us are doctors.

If your doctor said you're fine, no cause for concern, and you don't believe him, then get a second opinion.