Abstract: The course of sexual reproduction of Chinese fir × Cryptomeria (Cunninghamia lanceolata × Cryptomeria fortunei) is systematically reported in this paper. The observations are summarized as follows.1 . Chinese fir is different from Cryptomeria in development time of the megaspore and the microspore. Cryptomeria flowers earlier than Chinese fir, thus their flowering seasons are different.2 . It has been found that the pollen grains of Chinese fir and Cryptomeria and those of their hybrid (Cunninghamia lanceolata×Cryptomeria fortunei) are different in shape, size and convex under the scanning electron microscope.3. Most of the pollen grans of the Cryptomeria are able to stay at the micropyle of Chinese fir and they can develop to normal in the nucellus of Chinese fir under controlled pollination.4. It takes the ovule of Chinese fir eight months from receiving the grains of Cryptomeria to forming hybrid seeds. In Nanjing Chinese fir is pollinated in the last ten days of March and the gametophytes develop from April to the middle of June. In the first or second ten days of June, it is fertilized. The proembryo begins to develop in the last ten days of June, and early differentiation of the late embryo is in the last ten days of July. The embryo matures in early September and the seeds are collected in November. Each phase of development is normal.5. The development stages and morphological characters of the hybridized embryo are very similar to those of Chinese fir in sexual reproduction. It possesses the general characters of the embryo development in Taxodiaceae. This shows that both of the species are close in consanguinity and that the outbreeding has been believed to be successful between Cunninghamia and Cryptomeria,