A bracket and head rail assembly is provided. A recess is formed at both ends of the upper portion of a head rail. The recess is sunken at both sides to form a first slot and a second slot. The bracket includes a body and a fastener, wherein a claw is extended from the body, and an elastic part is extended from the fastener and bears against the body, such that the fastener is slidably disposed in the body. When being assembled, the first and second slots are easily locked with the claw and the fastener, and alternatively, they are exchanged with each other for locking with the claw and the fastener respectively. Then, the head rail and the fastener are designed into a thin configuration, and then, formed by bending and processing sheets, so as to achieve the advantages of simple assembly, mass production, and nice appearance.