To improve the service life of continuous casting crystallizer, the NiCo-ZrB 2 coating was prepared using nanocomposite plating technology. Uniformly dispersed nano-ZrB 2 particles significantly enhanced the hardness and wear resistance of the coating. Upon testing, the hardness of the coating exceeded 700 HV, with a friction coefficient below 0.2, which was superior to those of pure NiCo or other nanocomposite NiCo coatings reported previously. Microscopic analysis revealed that the addition of dispersants and ultrasonic vibration treatment had facilitated the homogeneous distribution of nano-ZrB 2 within the matrix, thereby promoting the formation of numerous nano-twins. Due to dispersion strengthening, fine grain strengthening, and twinning strengthening, the wear behavior of the coating changed from fatigue wear to abrasive wear, and the wear volume was significantly reduced by 82%. The above findings could potentially extend the service life of the coating, reduce the cost of steel loss per ton, and have broad application prospects in other surface protection fields.