As the result of earth environmental evolution, some deciduous broadleaf species are able to remain naturally in evergreen broad-leaved forests, but the reason for their survival is unclear. This study examined the responses of leaf morphology and photo-physiology of seedlings of a deciduous broadleaf species Liquidambar formosana and an evergreen broadleaf species Gordonia acuminate to three natural light regimes (open, gap and understory), in the purpose of elucidating eco-physiological mechanism of the survival of the deciduous species in the evergreen broadleaf forest. The main results are as follows: ①Compared to the evergreen species, the deciduous L. formosana had lower leaf mass per unit area (LMA), and higher Photosynthetic nitrogen use efficiency (PNUE). And in high light regimes it did not suffered from photoinhibition and showed a high photosynthetic plasticity, especially in gap, performed three times higher Pnmax in the evergreen species. Therefore, the deciduous species should be able to accumulate more carbohydrate in its shorter growth season, thus enhancing its competition ability; ②In the open site, the evergreen species displayed greater LMA, and suffered from photoinhibition, and allocated more nitrogen into chemical defense. Moreover, it showed a relative higher Pnmax in the gap and understory than in the open site, suggesting its preference to the gap and understory environments. Also, growing in the understory it allocated more nitrogen for survival which turns out to be much more important than growth. In contrast, in the understory the deciduous species displayed a low activity of Rubisco and thus a low photosynthesis. ③In the gap, the seedlings of both species exhibited a greater photosynthetic acclimation, a photosynthetic capacity (Pnmax) and the reasonable leaf nitrogen allocation coefficient in relation to photosynthetic activity suggesting that the gap is the optimal environment for their regeneration. However, the photosynthesis of the deciduous is more dependent on light and that of the evergreen is more on CO2 concentration. ④It is concluded that the deciduous broadleaf species with higher morphological and photosynthetic flexibility should be able to compete with the evergreen broadleaf species and hence survive in evergreen broadleaf forests.