The effect of water retaining agent (Guilspare) of different dosage (0, 2, 4 and 6 L/m²) combined with Pisum sativum Linn returning to field on soil water retention capacity, fertilizing ability, tobacco agronomic and economic characters and chemical composition were investigated in town of Pingding. The results showed that water retaining agent significantly slowed the water loss process of soil, soil retention capacity were 4 L/m² > 6 L/m² > 2 L/m². Water retaining agent reduced soil pH, increased the contents of soil organic matter, total nitrogen, total phosphorus, available nitrogen, available boron and potassium, 4 L/m² water retaining agent combined with green manure returning enhanced soil organic matter content of 6.07~28.3 times compared to single green manure return, soil fertility improved mainly because of the increased biomass of Pisum sativum Linn. 4 L/m² water retaining agent with Pisum sativum Linn returning to field increased the thickness or weight of tobacco leaves which improved the quality of flue-cured tobacco. The rose output of 4 L/m² treatment was by 10.30%. As to the influence of water retaining agent with Pisum sativum Linn returning on chemical composition of flue-cured tobacco, the nitrogen and potassium content in middle leaves were 1.67% and 2.24% processing with 6 L/m² water retaining agent with Pisum sativum Linn return, had reached the level of high-quality tobacco (the total nitrogen content of 1.5%~2.5%, potassium >2.0%), furthermore, it reduced the ratio of sugar and nicotine, increased the ratio of chlorine and potassium, by which increased the coordination of acid and alkaline substances in flue-cured tobacco. The application of water retaining agent with green manure returning increased the comprehensive quality of the lower leaves, and reduced the quality of the upper and the middle leaves, it might be caused by the shortage of soil moisture and fertility supplied to the middle and upper leaves in soil of newly reclaimed land.