Abstract: The dormancy of cotton seeds is influenced by heredity and environment. Five different types of cotton varieties are planted in two different zoology areas where are the southwest and the northwest of Shandong. To harvest cotton seeds in different growth periods and to make the planting experiment in the forcing house. To research the dormancy character of cotton seeds by the rate of seeds germination and fresh ungerminated seeds. The results showed that, the degree of seeds dormancy is deep in the rainy and high humidity condition; the degree of Bt cotton seeds dormancy is deeper than non-Bt cotton seeds,; the degree of seeds dormancy that harvested before Sep 10 and after Oct 10 is deeper than what is harvested during the period; the degree of seeds dormancy of late-germination insect-resistant cotton is deeper than conventional insect-resistant cotton; the degree of insect-resistant hybrid cotton seeds is similar as the conventional insect-resistant cotton seeds.