Abstract: Soil-cultured and sand-cultured cucumber seedlings were used in the experiments to study effects of CO₂ enrichment on absorption and distribution of mineral elements. The results showed that: CO₂ enrichment for 3 h every morning or 6 h every day at 1100±100 μL/L made the content of most mineral nutrients in different organs of cucumber seedling decreased; Prolonging CO₂ enrichment time led to the much lower content. However, as a result of CO₂ enrichment, the absorption ability of cucumber seedling was strengthened and the total amounts of mineral nutrients absorbed increased, the more the enrichment time, the more the absorption amounts were. It is suggested that more mineral nutrients should be applied when CO₂ enrichment is carried.