Objective The retrospective analysis was carried out to evaluate the results of humeral intercondylar fracture treated with AO reconstruction plate internal fixation accompanied by anterior transposition of the ulnar nerve. Methods From March 1996 to September 2001, sixty-eight patients diagnosed as humeral intercondylar fractures were treated in our hospital, forty-three of which were followed up and evaluated. By AO/ASIF classification, there were type C1 in 14 cases, type C2 in 18 cases, and type C3 in 11 cases. There were 18 male and 15 female patients with an average of 41 years ranging from 18 to 65 years. The patients were open fracture in 7 cases and closed fracture in 36 cases, of which were associated with humeral shaft fracture in 4 cases, Colles fracture in 5 cases, Monteggia fracture in 3 cases, olecranon fracture in 5 cases, and ulnar nerve injury in 6 cases. They were treated with open reduction and AO reconstruction plate internal fixation combined with routine anterior transposition of the ulnar nerve followed by early CPM mobilization. Results The mean follow-up of the group was 17.7 months ranging 12 to 37 months with bone union in 12 to 18 weeks. The outcome was evaluated with Aitken-Rorabeck rating system, 33 of which were graded as excellent, 4 cases as good, 5 cases as fair, 1 case as poor, as a result, the elbow function was excellent to good in 86.1%. One case experienced three degrees cubital varus without an influence on function of the elbow. The wound infection occurred in three cases healed following dress change. A heterotopic ossification developed in two cases 4 weeks later after operation. The preoperative ulnar nerve palsy recovered in all 6 cases, and there was no delayed ulnar nerve palsy happened postoperatively. Two elbow joints were restricted during extension to flexion activity by 43 degrees and 62 degrees respectively. Conclusion Intercondylar fractures of the distal humerus should be treated surgically as early as possible. Anatomical reduction, rigid fixation and early CPM exercise are the key prognostic factors, which could improve the elbow function. Otherwise routine anterior transposition of the ulnar nerve may be helpful to reduce the incidence of delayed ulnar nerve palsy.