Objective: The foot, as a critical component of the human kinetic chain, plays essential roles in supporting body weight, absorbing impact, transmitting motion, and maintaining balance, forming the foundation for upright locomotion. This study designed and validated a novel foot torsion measurement device, aiming to provide a high-precision, portable, and versatile biomechanical assessment tool for various scenarios. The device integrates a high-sensitivity torque sensor, adjustable angle set, and a dual-bearing rotational system to enable real-time measurement of foot inversion-eversion torque, angle, and stiffness. Methods: The experiment was conducted with 32 participants performing repeated measures during sitting and standing postures to test the reliability. Results: Results showed excellent intra-rater reliability, with ICCs for torque and angle ranging from 0.92-0.98 and 0.85-0.95 (dominant foot), respectively, with similar values in the non-dominant foot. Standard error of measurement (SEM: 0.15-0.24Nm for torque; 0.13°-0.30° for angle) and minimal detectable change (MDC) were low in all the parameters. Torsional stiffness exhibited large variability (ICC: 0.32-0.91), while total stiffness ICCs ranged from 0.49–0.85, during sitting conditions outperforming standing posture. Inter-rater reliability showed moderate ICCs for torque and angle (up to 0.78 and 0.74, respectively), whereas stiffness parameters remained low, suggesting the limited consistency across days, which requires further optimization of the device. Conclusion: The consistently observed low SEM and MDC values suggest that the sensitivity to detect subtle biomechanical changes in the foot complex. To sum up, the novel device demonstrated high precision, multifunctionality and portability, indicating strong potential for the application in injury prevention, rehabilitation assessment, and biomechanical research. Future work shall focus on optimizing dynamic measurement and expanding sample size to validate the application under the clinical settings.