Soluble sugars,free amino acids and proline were determined in tifdwarf（Cynodon dacytlon × C.transvaanesis）and seashore paspulum（Paspulum vaginatum Swarfz）under Si addition and shading treatments in media culture to study the influences of Si on the shading tolerances of turfgrasses.The results showed that content of total soluble sugars,sucrose and reductive sugars were significantly (P<0.05) decreased,while free amino acids were significantly (P<0.05) increased after shading treatment in tifdwarf and seashore paspulum.The differences between CK and shading decreased after Si application.Content of proline was significantly (P<0.05) increased by Si application but decreased less by shading.The content of total soluble sugars,sucrose,free amino acids and proline were significantly (P<0.05) higher in tifdwarf than that in seashore paspulum.Less effect was observed in tifdwarf than that in seashore paspulum after Si addition and shading treatments.These results indicated that the non structural carbohydrates dropped under shading stress which was restored by the higher energy utility induced by Si deposition,thus Si enhanced the shading tolerance of turfgrass.The results also showed that the shading tolerance of tifdwarf was higher than that of seashore paspulum.