Fundamental research on rock physics indicates that rock elastic features are essentially determined by its physical properties like mineral contents，texture，porosity，pore fluid and so on. However，rock physical properties are closely related to and affected by its sedimentary environment，process and consequent diagenesis history. Study on the influences of rock sedimentary features on its elastic parameters will be beneficial to reservoir prediction using seismic elastic parameters.Taking a fan-delta sandy conglomerate reservoir，the impacts of the rock physical parameters like lithology and pore fluid on its elastic parameters like density，velocity and modulus were analyzed systematically through rock physics analysis technique. The results show that velocity ratio of compressional and shear wave，shear wave impedance，shear modulus and μρ（the product of shear modulus and density）are sensitive to sandy conglomerate and mudstone，which can be used to predict the distribution of sandy conglomerate. The velocity ratio of compressional and shear wave and λρ（the product of Lame constant and the density）can be used to discriminate oil layer from water layer and to predict oil layer. Further research demonstrates that the correlations of velocity and impedance with rock porosity are becoming better when the multiple sedimentary cycles of stratigraphic sedimentary sequences are divided finely into single cycle. But their relationships are not linear and affected apparently by shale content.