A quick install nut is provided. The nut includes an entrance end, an exit end, a first threaded portion corresponding to the entrance end, a second threaded portion corresponding to the exit end and connected with the first threaded portion. The first threaded portion includes a first slot, a segment of first internal thread formed in the first slot, and a first relief space communicating with the first slot radially. The second threaded portion includes a second slot, a segment of second internal thread formed in the second slot, and a second relief space communicating with the second slot radially. The first and the second slots are disposed on a central axis in a staggered manner. A compression wall is formed on the first threaded portion. After being tilted, the nut is placed and moved along a threaded fastener and returned to achieve fast and firm fastening.