Provided is a crystalline form E of ertapenem sodium. Further provided is a method for preparing a crystalline form E of ertapenem sodium, characterized by using an aqueous ertapenem sodium solution at a low concentration as a raw material. The crystalline form E can be easily filtered and dried, the properties in the drying process are stable, and the purity of the crystal is high and can be up to 98.5% or higher.
