This study aims to determine the effectiveness of learning to write the text explanation of the complex media using adobe flash the students of class XI SMA Negeri 2 Sebulu. Sources of data in this study were obtained from: (1) the respondents, namely: the students of class XI MIPA 3 and XI IPS 3 SMA Negeri 2 Sebulu, (2) informants, namely: validator, students and teachers of bahasa Indonesia SMA Negeri 2 Sebulu, (3) Documents, namely: specialized textbook, a recapitulation of the value of student learning outcomes and the value of the written text explanation, and library books. Instrument the effectiveness of media use adobe flash using the objective test. Data analysis techniques using descriptive statistics. Based on the analysis of the data obtained the results of the assessment of the cognitive aspects and the assessment write text explanation of the complex has been done in class XI SMA Negeri 2 Sebulu with reference to the criteria of effectiveness in this study, it is known that media-based learning adobe flash effectively used in writing the text of the explanation and improve student learning outcomes. This can be seen in the results of the assessment of cognitive aspect obtained the average value of on the initial test of 59 and 85 on the final test. Further assessment of writing skills text eksplansi complex acquisition of the average results of the write with the value of the initial test 67-test and final test to be 85.