The main requirements is the contract between you and company you are working for and the type of your visa. If you're working visa is under low category such as Laborer, driver and other small salaried categories then you are not eligible to apply.

If you have a working contract and your salary is minimum Qrs. 4500.00 (should be supported by 6 months bank statement) then you are eligible to apply however it will still depend on your company because the ministry of labor will require the NOC (non Objection certificate) from your employer that they dont have any objection for you to get your family. The main objective for this is to make sure that, you are capable of giving your family a decent life here in Qatar.

I hope it could help.