A card edge connector includes a first insulating housing loaded with a plurality of first terminals, a second insulating housing loaded with a plurality of second terminals. A card receiving slot is defined between the first insulating housing and the second insulating housing with a key disposed in the card receiving slot. The first terminals and the second terminals are disposed at two opposite sides of the card receiving slot and comprising contacting portions extending in the card receiving slot. The first insulating housing defines a pair of locking arms at opposite ends thereof and extending towards the second insulating housing, the second insulating housing defines a pair of locking recesses, the locking arms are locking with the locking recesses thereby the first and second insulating housing are snugly attached together.