Abstract: Objective: To detect the 17p11.2-p12 duplication in Chinese Charcot Marie Tooth 1 patients, and to analyze the clinical feature of the patients.Methods: Extract DNA from the peripheral white blood cell of 29 members from 15 CMT1 families. The CMT1A duplication were detected by PCR-STR quantitative analysis of 3 STR markers in 17p11.2-12 rgegion. Sensitivity of different marker was compared. Clinical features of patients diagnosis to have the CMT1A duplication were analysed. Results: In 16 patients who were diagnosed clinically and electrophysiologically as CMT1 we found 9 (56%) with the CMT1A duplication. Duplication was detected in 4 of the 13 non-symptom family members. Study of 100 normal controls shows a heteroxygosity of 85%, 77% and 80% for the 3 markers RM GT, D17S1357 and D17S1358, and polymorphism is 7, 7, 6 respectively. Conclusion: CMT1A is the most common subtype of CMT in Chinese group as in other races. STR quantitative analysis of markers on different sites in 17p11.2-p12 region provides a sensitive and reliable method for detection of CMT1A duplication. Clinical Chinese group as in other races. Detection of the duplication represents a very useful tool for diagnosis of CMT1A, especially for those without clear menifestations of clinical symptoms.