The　permeability　of　saturated　soils　has　great　influence　on　the　velocities　and　attenuation　characteristics　of　fast　compressional　wave　P1,　low　compressional　wave　P2,　and　shear　wave　S　in　saturated　soils,　respectively.　In　three　different　cases,　namely　zero,　finite,　and　infinite　permeability,　the　wave　equations　and　theoretical　velocities　of　P1,　P2,　and　S　wave　in　saturated　soils　are　given　based　on　the　u-w-p　equation,　respectively.　According　to　the　solutions　of　the　wave　equations,　the　real　velocities　and　attenuation　coefficients　of　three　waves　are　redefined,　respectively.　In　different　saturated　soils,　the　influences　of　the　permeability　and　the　loading　frequency　on　the　wave　velocities　and　attenuation　are　discussed,　respectively.　Moreover,　the　suitable　application　scope　of　the　u-p　equation　is　discussed　based　on　different　permeabilities　and　loading　frequencies.