Abstract: Criminal lawyer professionalization includes defender specialization，business division specialization，and legal service specialization.In America，which has realized criminal lawyers professionalization，there are three characteristics：strict requirments for professional qualifications，precise division of professional duties，and professional legal service.In contrast to the US practice，there are a lot of hindrance to the professionalization of criminal defense lawyer：the inadequate development of the Bar，the lack of indemnificatory system and the incentive mechanism，and the complexicity of lawyer′s practice environment，etc.These obstacles can only be surmounted after long and unremitting efforts.

Key words: lawyer, criminal defense, professionalization, legal profession, professional qualification 