Though some hypotheses have obtained theoretical and empirical supports, it remains largely unknown in the aspect that how deception increases orchid fitness. This study used food-deceptive Papilionanthe teres as experimental material to explore the ecological significance of orchid deceptive pollination. Deception together with obvious pollinarium bending increases P. teres fitness by means of decreasing geitonogamy under the natural conditions. The proportions of full seeds, single fruit weight and seed weight per fruit after self-pollination and nectar addition were significantly lower than that after cross-pollination and natural conditions (all p ＜ 0.05). Seed viability (seed growth and development rate) after cross-pollination and natural condition were significantly higher than that after self-pollination and nectar addition (all p ＜ 0.05). However, there was no significant difference in all the above parameter values of fruits and seeds between cross-pollination and natural conditions (all p ＞ 0.05). These results confirmed that P. teres has high level of genetic load, and self-fertilization or geitonogamy will cause serious inbreeding depression. These conclusions support the outcrossing hypothesis that ecological significance of P. teres deception is to promote outcrossing and improve the ability of the offspring to adapt to the environment.