Objective To evaluate the effectiveness and safety of external fixation (EF) and open reduction and internal fixation (ORIF) for unstable distal radius fractures in adults. Methods We searched MEDLINE (1966 to September 2008), Cochrane Central register of controlled Trials (The Cochrane Library, Issue 3, 2008), EMbase (1974 to September 2008), CBM, CNKI, and collected randomized controlled trials (RCTs) of EF and ORIF for unstable distal radius fractures in adults. The quality of the included studies was critically assessed and data analyses were performed with the Cochrane Collaboration’s RevMan 5.0 software. Results Seven RCTs involving 634 patients were included, of which 269 were in EF group, and 293 were in ORIF group. Only 1 study had relative high quality, all the others had some limitation in randomization, blinding, and allocation concealment. The results of meta-analyses showed that, 1) about the effectiveness: according to the Gartland and Werley grade standard, the ORIF group was better than the EF group with statistic difference (RR=1.50, 95%CI 1.11 to 2.03, P=0.008); because of the original studies did not offer the detailed data including pad strength, grip strength, flexion-extension, radial deviation, and ulnar deviation, we only processed a descriptive analysis; and 2) about complications: the infection rate of the pin track was higher in the EF group than that in the ORIF group with statistic difference (RR=0.24, 95%CI 0.08 to 0.76, P=0.02); but there were no differences between the two groups in reflex sympathetic dystrophy (RSD) (RR=0.88, 95%CI 0.30 to 2.56, P=0.82), extensor tendon rupture (RR=3.93, 95%CI 0.45 to 34.62, P=0.22), and compartment syndrome (RR=3.13, 95%CI 0.51 to 19.09, P=0.22). Conclusions Compared with EF, ORIF is much better based on Gartland and Werley grade standard, and causes much less infection. Because of the limited quality and quantity of the included studies, more proofs are required from more RCTs with large sample.