@Aya dh ,
Do they have specific objections about your boyfriend? How old is he?
As Max wrote, your parents are only looking out for what they believe is your best interests. Maybe they see something in this guy that is giving them some concern. Maybe that concern is well founded, maybe it is not.
When I started seeing my wife, she was only 16 and I was 20. Her parents were concerned that someone my age was out for only one thing from their daughter and did not want their daughter seeing me. I understood why they were concerned and rather than sneak behind their backs, we talked to them about it and came to an agreement that I could spend time with her only at their house when they were home, but we could talk by phone each evening. In other words, I worked with her parents to allay their fears rather than sneaking behind their backs.
So bottom line, if you really have feelings for this guy, talk to your parents about it. Ask them if they have objections to this particular guy or if they just feel you are too young to have a boyfriend. In the meantime, there is nothing wrong with keeping him as a friend and they may be willing to have him over to your house on weekends to visit and spend time with you.