Abstract: [Objective] When selecting the materials of establishing timber forest advanced-generation seed orchard, The initial focus was on timber's fast-growth, rather than the flowering phenology of superior tree. During the establishment of the advanced-generation orchard, the clone arrangements are usually based on the flowering phenology genetic factors of its provenance in a large scale. Even clones of same provenance on a small scale, the flowering phenology can not be absolutely synchronized, rather than that in large-scale. Therefore, understanding the flowering phenology of clonal seed orchard can provide some evidences for intensive cultivation, yield prediction, seed genetic quality regulation of the seed orchard.[Methods] Ten clones of Pinus massoniana were randomly selected from Region I and twenty five clones randomly from Region V with different type in Guiyang Pinus Massoniana Second-Generation Seed Orchard from 2012 to 2013, then observed their flowering phenology.[Result] The results showed that there were differences in commencement and ending dates and durations among different clones of female and male flowering phase, but a certain synchronicity in whole flowering phase between female and male of 35 clones, and also in sync roughly in their initial flowering stage, and total synchronization occurred in their full-bloom stage and last flowering stage. The difference in flowering phase among individuals was larger than that among clones. While the individuals who had an earlier male flowering period appeared to have also an earlier female flowering period. There were certain synchronicity between male and female from the same strain of parents in generation orchard. In addition to a weak negative correlation between the late flowering stage of female cones and the initial flowering stage of male cones, there were highly significant or significantly positive correlations between male and female of their initial flowering stage and full-bloom stage and last flowering stage. The extent of correlations decreased in sequence of the correlation between initial flowering stage and full-bloom stage, the correlation between full-bloom stage and lasting flowering stage, and the correlation between initial flowering stage and lasting flowering stage. The correlative coefficient of initial flowering stage of female and initial flowering stage of male was the greatest. Slope positions showed significant affect on the flowering period of the mother tree. Among the entire individual grows in different slope positions, there were obvious differences between the flowering value of male and female. The differences listed in order of small to large are:upper slope, middle slope, and down slope. The effects of slope positions on flowering period in a sequence from high to low degree were initial flowering stage of female, initial flowering stage of male, full-bloom stage of female, full-bloom stage of male, lasting flowering stage of both male and female. The flowering period of clones came from farther north origin was comparatively earlier. Among different type of clones there were significant differences in male full-boom stage and female initial flowering stage, but no significant difference was found in male initial flowering stage and lasting flowering stage, as well as female full-bloom stage and lasting flowering stage. Both in female and male flowering period, there were large differences yearly. The earliest flowering period in 2012 was 25 days in advance of that in 2013.[Conclusions] There were fairly good synchronicity in the whole flowering phase between female and male of 35 clones in Guiyang Pinus Massoniana Second-Generation Seed Orchard. Concerning the field of flowering phenology, it was quite reasonable in selecting the materials of establishing the generation orchard, and had no affect on yield prediction, seed genetic quality.