The purpose of this study is to find an authentic assessment in field study activities that can be used to shape the professionalism of geography teacher candidates. The method used in this research is Research and Development. Research instruments: documentation study guidelines; model authentic assessment; Instruments for prospective professional teachers with peer ratings. Authentic factual model assessment limited testing of students at the Jakarta State University Geography Education. The factual model was improved to be retested. The hypothetical model was tested on 120 respondents in geography education students at Jakarta State University & Indonesian Education University. Data analysis used by path analysis, with the help of AMOS software program 5. The type of authentic assessment is positively related, namely the performance appraisal of tool use (0,36) and project assessment (0,24), which has a negative relationship namely attitude assessment (-0,13), presentation performance (-0,14), and portfolio assessment (-0,40). Teacher professionalism includes four competencies. Field study can make personality and social competencies of geography teacher candidates, but it lacks in making pedagogic and professional competences.