The invention relates to a paraffin sectioning method for an ocean shellfish D-shaped larva, which comprises the following steps: (1) Boulin solution is added to a container having an ocean shellfish D-shaped larva sample, and then alcohol with mass percentage concentration of 70% is added so as to obtain a fixed ocean shellfish D-shaped larva; (2) the fixed ocean shellfish D-shaped larva is wrapped up and is placed in a sample embedding box, and the sample embedding box is placed in a dehydrator or a staining jar; and then the steps of dehydration, transparency and wax impregnation are carried out; (3) embedding and sample location are carried out; (4) slicing and drying are carried out; and (5) a hematoxylin-eosin counterstaining method is adopted for dying. The paraffin sectioning method is simple and practical, has short processing time and transitional steps, leads all tissues of the larva to be gradually and completely immersed by reagent, well keeps the original state and structure of the tissues of the larva and provides a practical and effective technical means for research on early stage embryos and larva development of shellfishes.