Abstract: Caltha dysosmoides is a newly named species in 2016 (specific to Sichuan).For the protection and use of this new species,the urgent need is to study their reproductive biology.In this paper,50 strains were selected from different populations to observe their floral characteristics,pollen viability and stigma receptivity.The pollen viability was measured by TTC method,and the pollen culture of Caltha was cultured in liquid medium,and the stigma receptivity was determined by benzidine hydrogen peroxide (until it was inactive).The results of the investigation showed that under natural conditions,the Caltha bloomed from April to May,and the flowering period of one flower is generally 2 days.Stamens were shorter than pistil; Anthers were close to the outer side of the stilus with a distance of about 3 mm; In the whole process of flower opening,the relative position of the pistil and stamen were invariant; In the morning,pollen viability was significantly lower than in the afternoon,and increased rapidly in 1~4 hours after anthesis,after 4 hours,the pollen activity increased slowly.The stigma could be granted,and it would be relatively strong at 3 hours after anthesis.