Abstract: Objective: To investigate the optimal exposure parameters for ultra-high-resolution computed tomography (U-HRCT) in wrist joint imaging. Methods: A wrist joint phantom composed of self-made ballistic gelatin and adult wrist bones was used as the imaging object. The phantom was scanned using both U-HRCT and multi-slice spiral CT (MSCT). For U-HRCT, the tube voltage was varied from 60 to 100 kV in 5 kV increments, while the tube current ranged from 2 to 10 mA in 2 mA increments, with a fixed exposure time for image acquisition. For MSCT, routine wrist CT scanning was performed at 120 kV using automatic tube current modulation (ATCM). Thermoluminescent dosimeters (TLD) were used to measure the radiation dose delivered to the wrist phantom during each exposure under both scanning protocols, and the average value from two TLD measurements was recorded. The figure of merit (FOM) was subsequently calculated. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), background noise (SD), dose–area product (DAP), entrance surface air kerma (K_a,e), and FOM under different exposure conditions were analyzed to determine the optimal exposure parameters. Results: At an exposure setting of 60 kV and 2 mA, the CNR, SNR, DAP, and K_a,e values were the lowest, measuring 3.5, 5.4, 23.68 mGy·cm², and 0.40 mGy, respectively. At 100 kV and 10 mA, the CNR, SNR, DAP, and K_a,e values reached their maximum values of 13.8, 18.1, 368.75 mGy·cm², and 12.21 mGy, respectively. The SD was highest at 383.8 under 60 kV and 2 mA, whereas it was lowest at 64.7 under 100 kV and 10 mA. The maximum FOM value of 84.3 was achieved at 70 kV and 2 mA. Under the 70 kV and 2 mA condition, the K_a,e value was 0.73 mGy, compared with 5.48 mGy for MSCT. Calculations showed that the K_a,e of U-HRCT was reduced by approximately 86.68% relative to MSCT. Conclusion: Tube voltage and tube current significantly affect both image quality and radiation dose in U-HRCT imaging. The exposure setting of 70 kV and 2 mA can satisfy clinical diagnostic requirements while substantially reducing radiation dose to the subject, and is therefore recommended as the optimal scanning protocol for U-HRCT.