Learner center assessment procedure and application is very crucial for students writing skills improvement. Hence, this study aimed to explore the effects of dynamic criteria mapping assessment on students' conceptions and writing skills development with reference to Vygotsky, zone of proximity development. To examine the issues, time series, quasi experimental research design was employed. The major data gathering tools were pre and post-tests, questionnaire and focus group discussion. Multistage sampling technique was employed to choose the sample of the study, and 63 first year software engineering students were the subjects of the study. Among these participants, 32 students were assigned to experimental group and the other 31 students' were assigned to control group. The findings indicated that dynamic criteria mapping assessment was effective in improving students writing skills development; students were able to construct sentence with better text structure and arguments. Furthermore, they used various cohesive devices, appropriate punctuation marks and dictions in their writing. Moreover, the assessment techniques had changed their conceptions on learning writing skills and engagement in writing assessment. Generally, the researcher learned that dynamic criteria mapping assessment strategy was vital to enhance students writing skills and conceptions on learning writing skills. Lastly, it is recommended that teachers should prepare various and dynamic criteria with their respective students while they assess their students writing skills, and teachers should not use judgmental assessment techniques.