A card edge connector includes an insulative housing, a number of contacts and a pair of locking arms for holding a card. Each locking arm includes a retaining portion fixed to the insulative housing and a resilient arm extending forwardly from the retaining portion. The resilient arm is deformable outwardly so as to lock or unlock with the card. The resilient arm includes an engaging portion extending inwardly and a hook at a front of the engaging portion. The engaging portion includes a downwardly inclined surface for guiding installation of the card. The hook protrudes upwardly beyond the engaging portion so that when the card is not so inserted along a card-insertion direction, even if the card is downwardly pressed, a top edge of the hook resists against the card so as to prevent the card from further downward movement.