Teacher assessment literacy is a key factor in the success of teaching, but some studies concluded that teachers lack it. The aim of this research is to propose the ''Practicing, Reflecting and Revising with WATA system (P2R-WATA) Assessment Literacy Development Model'' for improving pre-service teacher assessment literacy. WATA system offers personalized learning resources and opportunities for pre-service teachers to assemble tests and administer them to students on-line. Furthermore, WATA system facilitates performance of test analysis and item analysis, and enables pre-service teachers to review statistical information from the test and item analyses to revise test items. Sixty pre-service teachers participated in this research. The research results indicate that pre-service teachers using P2R-WATA Assessment Literacy Development Model have better effectiveness in improving their assessment knowledge and assessment perspectives.