As a type of new flexible protective material，geocell has broad application in slopes of highway. Eroding model experiment shows，by adding geocell，not only can the total average erosion rate be decreased to 48% but also gulches development and evolution are weakened，thus the collapsing of roadbed is avoided. Foundation bearing capacity of saturated loess test indicates，by the same way，that loess slopes of highway will double or treble its capacity and limit its failure to local or slobaal shear failure. Many practical engineering examples have proved，as a type of flexible protective material，that geocell has good effects on slopes of highway.