In this paper, the model of a three-terminal nanowire refrigerator is established based on one-dimensional (1D) ballistic conductor. It is composed of an intermediate cavity and left/right electron reservoir in which the intermediate cavity and left/right electron reservoir are connected by 1D nanowire conductor. The expression for the charge current and that for the energy current flowing from two electron reservoirs are derived by using Landauer formula and basic thermodynamic laws. Then, the working region of the refrigerator is obtained, its performance characteristics are analyzed, and its performance optimization is discussed. It is shown that the refrigerator under different parameters operates in different working regions. For each refrigeration region, there is an upper limit of temperature difference, and the refrigerator will be unable to refrigerate beyond the upper limit. The characteristic curve of the cooling rate changing with performance coefficient is a loop-shaped one, which provides an important index for us to evaluate the performance of the refrigerator. The energy level width of the nanowire can be reduced as much as possible, which will improve the performance of the refrigerator.