【Objective】To unveil the pollination characteristics of the Chinese endemic rare and endangered aquatic plants Ottelia acuminata and Ottelia acuminata var. crispa, to investigate their adaptive relationship with pollinators, to elucidate the factors affecting the success of pollination, and to provide theoretical and technological guidance for the hybrid breeding of the two species；the study of hybrid affinity between the two not only provides insights into their cross-breeding dynamics but also serves as a valuable reference for broader studies involving cross-breeding and germplasm conservation within the genus.【Methods】Ottelia acuminata and Ottelia acuminata var. crispa were used as research subjects to study their pollination characteristics and hybrid affinity by observing their flowering dynamics, insect flower-visiting behaviors, determining pollen viability, stigma pollinability, and bagging test.【Results】The flowering dynamics of Ottelia acuminata and Ottelia acuminata var. crispa were basically similar, with single-flowering periods of 7-11 h. The main flower-visiting insects of both species are Episyrphus balteatus, Apis cerana, Bombus sp. and Coccinella sp；The trend of pollen viability and stigmatic accessibility of the two plants was consistent, both showed an increasing and then decreasing trend, Ottelia acuminata pollen viability was the highest at 88.27%, Ottelia acuminata var. crispa pollen viability was the highest at 88.34%, and stigmatic accessibility of both plants was the highest in the anthesis Ⅱ；The fruit set rate of Ottelia acuminata and Ottelia acuminata var. crispa orthologous and backcrosses were 85.71% and 91.33%, respectively, and the hybrid affinity indexes were above 53, which proved that there was no hybridization between Ottelia acuminata and Ottelia acuminata var. crispa. The average number of seeds in hybrid single fruit was 54, 69, 73, 71 and 71 respectively; Among the hybrid combinations, Ottelia acuminata (♂) × Ottelia acuminata var. crispa (♀) combination had the highest thousand-grain weight of 3.334 g. Seeds of the hybrid combinations were subjected to germination experiments, and it was concluded that the Ottelia acuminata (♂) × Ottelia acuminata (♀) combination had the seed germination rate was the highest, 71.7%, and the other three combinations, the germination rate was lower, with an average of 23.2%.【Conclusion】Ottelia acuminata and Ottelia acuminata var. crispa have basically similar flowering dynamics, with shorter single-flowering periods and fewer pollinator species, which affects their sexual reproduction; hybridization experiments between the two showed no significant hybrid discordance.