Objective To study the diagnostic value of 3-dimensional CT reconstruction in posterior urethral strictures or ankylurethria.Methods Thirty patients with strictures or ankylurethria of posterior urethra caused by pelvic fracture underwent helical CT scan and 3-dimensional reconstruction of the urethral canal as well as radiographic urethrography before and post open urethral reconstruction to observe the urethral anatomy,the length and position of the urethral strictures,the depth of periurethral scar.Results The mean stricture or ankylurethria length measured by radiographic urethrography was 4.0 cm (range from 1.0 cm to 7.0 cm),and the correlation coefficient of stricture or ankylurethria length was 0.92,21 (70%) patients were diagnosed accurately by radiographic urethrography.The mean stricture or ankylurethria length measured by 3-dimensional CT reconstruction was 4.3 cm (range from 1.2 cm to 7.6 cm),and the correlation coefficient of stricture or ankylurethria length was 0.96,there were 28(93%) patients diagnosed accurately by 3-dimensional CT reconstruction.The mean stricture or ankylurethria length measured by open urethral reconstruction was 4.2 cm (range from 1.5 cm to 7.5 cm).Five patients with urethrorectal fistula were also diagnosed accurately by 3-dimensional CT reconstruction rather than by radiographic urethrography.Conclusions 3-dimensional CT reconstruction of the urethral canal can accurately evaluate the urethral anatomy,the length and position of the urethral strictures,as well as the depth of periurethral scar after crush injury and provide useful information for operation that may not be provided by radiographic urethrography.3-dimensional CT reconstruction may become the most valuable means for detecting posterior urethra strictures or ankylurethria with urethrorectal fistula.