[Objective]To evaluate the effect of treatment of unstable intertrochanteric fracture with dynamic condylar screw.[Method]Fifty-six cases of unstable intertrochanteric fractures were treated with typical ORIF (open reduction and internal fixation) with dynamic condylar screw from 2000 to 2004. According to the Evan's classification systems, there were 19 cases of Evan's Ⅲ fracture, 27 cases of Evan's Ⅳ fracture and 10 cases oblique reverse Evan'sⅤ fracture. The average period of follow-up was 10 months (8～15 months).[Result]All cases had union with average union time of 4 months, no coxae inversion, fixation failure and fracture nonunion. The satisfactory rate of function was 89%. [Conclusion]For unstable intertrochanteric fracture,including Evan's Ⅲ, Evan's Ⅳ and oblique reverse Evan'sⅤ fracture, using DCS is a good method to improve the clinical results.