This study has used minimizing input-oriented Constant Return to Scale and Variable Return to. Scale Data Envelopment Analysis (DEA) models with one output and fourth input variables were used to analyze cost efficiency (CE) for 62 pond of commercial black tiger prawn aquaculture in Song Cau town, Phu Yen province. The objective of the study was to how many percentage of ponds were cost efficiency in total of commercial prawn ponds, average optimal minimum cost which farmers have adopted strategies to suit. The empirical results indicate that if using CE - CRS, the proportion percent of pond efficient of Song Cau town, Phu Yen province is 1.61 percent, CE - CRS ratio is 0.42, and average optimal minimizing cost is 8,636,064 VND. If using CE - VRS, the proportion percent of pond efficient of Song Cau town, Phu Yen province is 6.45 percent, CE - VRS ratio is 0.70, and average minimizing cost is 18,704,759 VND. The study proposed with the model of CE - CRS, the pond can use these inputs more reasonable but still not diminish in terms of output produced with the optimum amount of average feed was 241.51 kg/season, the average optimal seed was 90,565. According to CE - VRS model, the average optimum feed was 635.11 kg/ season, the average optimal seed was 44,975.