My blood type is ab+, what type of blood should my future wife have in order for us to not have complication ? why do we need to do blood test?

Any: Nowadays, blood type is not a concern in choosing that one special woman. A mother who is rh negative may need special treatment to prevent problems but this is routine and almost always is highly successful. Look instead for someone that you like and with whom you can get along -- that's much more of a challenge than matching blood types! i wish you both happiness.

No specific type: Blood types are not a cause of problems in marriage and only rarely for the offspring. As and when you are ready to have a family your doctor can advise you about any risk to the baby based on your future wife's blood type. Choose a compatible wife without regards to her blood type.