Abstract: In order to better understand the forming of natural aeolian sand ripples,this paper had researched the shape characteristics of them by field observation and investigation,and analyzed the relations between shape characteristics of sand ripples and physical characteristics of surface sand.The models between shape characteristics of sand ripples and bulk density or mechanic composition of surface sand were constructed.Results showed that there was linear relationship each other among sand ripple's four attributes-wavelength,windward slope length,leeward slope length and height.Those attributes assume multivariate linear models with sand grain sizes of 3-1 mm,1-0.25 mm and 0.005-0.001 mm,and cubic functions with bulk density of surface sand.The bigger the average size of sand grain is,the higher and bigger the sand ripple is,and also the longer the wavelength is,or vice versa.Furthermore,the sand grain size of 1-0.25 mm in mechanic composition plays a major role in formatting and developing of natural aeolian sand ripples.