So basically my passport have only 1 main double entry visa that i got in my country before entering Thailand.Now 6 months later i want to make more 6month(1 more double entry).Is that possible or i can make only 3 months?(single entry)

Single Entry only, but if you go back to your Home Country you can apply for the new METV (Multiple Entry Tourist Visa)

Only single entry if you qualify .

Since November 13th when the multiple entry tourist visa was made available only a single entry visa is available unless you can qualify for the METV.

The double entry tourist visa has ended. You can only get single entry tourist visas locally to Thailand which will give you 60 days plus a 30 day extension.