A method for manufacturing graphene platelets includes the following steps of: providing a plurality of graphite blocks each including a plurality of stacked graphene layers, between every two graphene layers being a bonding formed by a van der Waals force; applying a shear airflow produced by an airflow interface formed between a first flow path and a second flow path by a forward airflow and reverse airflow to the graphite block, the shear airflow having an energy sufficient for damaging the van der Waals force to disengage a part of the graphene layers; and collecting a plurality of pieces of the graphene platelets, the graphene platelets including one or multiple of the graphene layers. Thus, the shear airflow of the present invention disengages the graphene layers from the graphite block to form the graphene platelets, thereby providing a simple manufacturing process and promoting mass production at a fast speed.