Abstract: Pumpkin normal strain‘Jinhui 2’（Cucurbita pepo L.）and hull-less mutant strain‘0516-2’were used to determine the difference of the testa development using paraffin section method. The results showed that both normal and hull-less mutant seeds developed a five-zoned testa after 10 days post-pollination. The development course of testa was different between normal and hull-less mutant seeds after 15 days post-pollination. The cell layers of hypodermal were increased in normal strain and the color of that stained. The cell walls of sclerenchyma and parenchyma tissue were thickened，strained. When the seeds were maturity，these tissues became hard and leathery hull. On the contrary，the cell walls of sclerenchyma and parenchyma tissue were not thickened in hull-less mutant strain，the cell of tissue were collapsed and formed a thin testa.

Key words: pumpkin, testa, development, anatomical structure