Azolla and Spirodela polyrhiza are both high-quality biological green fertilizers. Returning duckweed to the field is a green agricultural ecosystem management method that can increase soil organic matter and nitrogen content，thereby replacing or reducing the use of nitrogen fertilizer. However，the impact of returning Azolla and spirodela polyrrhiza to the field on ammonia volatilization and rice yield is currently unknown. To clarify the impact of duckweed returning to the field on ammonia volatilization and yield in rice fields，a pot experiment was conducted with 5 treatments，namely，local conventional practice(CT)，two types of green manure(Azolla and spirodela polyrrhiza)returning to the field(CTDA and CTDD)，Azolla-rice co-culture(CTA)，and CK. The daily flux and total amount of ammonia volatilization in the entire rice season，as well as the grain yield，straw yield，and biomass of rice were tested. The experimental results showed that:(1)Compared with CT，the Azolla or spirodela polyrrhiza returning significantly increased the total ammonia volatilization in the rice season(P<0.05)，with an increase of 25% in CTDA and 50% in CTDD，respectively. CTA treatment in rice fields reduced the total amount of ammonia volatilization during the rice season by 26.7%.(2)The treatment of returning Azolla or spirodela polyrrhiza to the field significantly increased rice grain yield，which was 1.54 and 1.64 times higher than the CT treatment，respectively. CTA treatment increased rice yield by 14.8%. In conclusion，returning Azolla or spirodela polyrrhiza to the field increased rice yield while increasing ammonia volatilization at the same time. Raising Azolla in rice fields could not only increase rice yield but also reduce ammonia volatilization.