<p>This study investigated the effectiveness and safety of ultrasound-guided non-incisional thread trigger finger release on cadavers using a newly developed domestic thread (Smartwire-01). Ultrasound-guided non-incisional thread trigger finger release was performed on 12 fresh cadaveric hands, including 12 thumbs and 48 long fingers. Two experts, experienced in an ultrasound-guided thread transecting technique, performed the procedures independently. The distal-to-proximal and proximal-to-distal approaches were performed in 6 hands each to determine which is safer and more effective. After the procedure, anatomical analyses were conducted by a blinded anatomist. The presence of a dissected A1 pulley and any damage to adjacent structures were assessed. Among the 60 cadaveric digits, 52 (86.7%) showed complete transection of the A1 pulley. The success rate for the thumb (66.7%) was relatively lower than that of the other fingers (91.7%). The distal-to-proximal approach showed a higher success rate (96.7%) compared to the proximal-to-distal approach (76.7%), with a near-significant difference (<i>p</i> = 0.052). Anatomical analysis revealed clear and sharp incisional margins of the transected A1 pulley, with only 1 minor flexor tendon injury observed, which occurred with the proximal-to-distal approach. Ultrasound-guided non-incisional thread trigger finger release using Smartwire-01 is a safe and effective procedure when performed with the distal-to-proximal approach, particularly in long fingers.</p>