From 2023 to 2024, this study conducted a systematic study on the number of wild, semi-range, and free-range Père David's deer, as well as the number of females in 304 harem groups during the rutting season in Dafeng National Nature Reserve. 99 semi-range groups, 109 free-range groups, and 96 wild groups were observed. Non-parametric statistics analysis was used to compare the three group types, exploring group stability and reproductive strategies differences by comparing the number of females and behavioral and habitat preferences. The results showed: (1) The mean number of females within harem groups was (30.94±26.45) per group, with significant differences among semi-range, free-range, and wild groups (P=0.034). (2) The three group types differed in terms of group stability. The number of groups with the highest group stability (N=159, P<0.01, 35.21±26.11 females per group) was greater than those groups with medium or low group stability. (3) Most females were resting during our observations, and there were significantly more females in the resting status than in the foraging or moving status (P=0.036). Behavioral conditions may be a response to the reproductive strategy of the two sexes. (4) There were significant differences in habitat preferences between semi-range groups & free-range groups (P=0.006), semi-range groups & wild groups (P<0.001), and free-range groups & wild groups (P<0.001), suggesting the significant differences in preferred habitats among the three group types. Females in harem groups favored grasslands, bare lands, and ponds than other habitats (P<0.001), with the highest number of groups preferring bare lands. This may be because bare lands may facilitate harem management by the α-male and are more conducive to rutting and mating than other complex habitats. In summary, the results suggested that the number of harem groups differed in behavioral status and preferred habitats during the rutting season. Furthermore, since the group stability during the rutting season can predict the mating and reproductive rates of the α-male, the stability of the number of females also reflects adaptive adjustments in Père David's deer breeding strategies, particularly those of the α-males. Three rewilding types of groups differed in group stability, the number of females in the harem group, behavioral status, and habitat selection. Therefore, we recommend that the rewilding of Père David's deer takes into account a reasonable habitat configuration and adequate space, as well as the restoration of wild populations through a gradual staged approach. This study explored the breeding strategies of semi-range, free-range, and wild groups in Père David's deer from the perspective of female numbers in harem groups and the group stability during the rutting season. Aim of this study is to provide scientific recommendations for the recovery of Père David's deer populations.