A slide rail kit is applicable to a rack. The slide rail kit includes a first rail and a locking member. The first rail is arranged with a mounting feature. The locking member is arranged on the first rail. The mounting feature is configured to mount the first rail to a mounting structure of the rack. The locking member includes a locking part and an operating part. The locking part is configured to be held in a state being blocked by the rack in response to an elastic force of an elastic structure. The operating part is configured to be operated to move the locking part away from the state being blocked by the rack.