Thank you!
It show me which partner is company.

But I want to inherit res.partner's create function to detect that the partner is created from the company and then add my custom data to some fields.

Instead of partner's create method, you can inherit company's create method and then you can write your datas in company "s partner.

For particular partner, you have to consider partner type and commercial_partner_id fields.

Thank you very much!
I inherited company's create method and my problem is solved.
I had a little trouble finding the company's create method because it is base method.
But I finally found it in odoo/addons/base/models/res_company.py.

Thank you!

Hi Anhnt,
Please vote up the answer.
Thank you.