Abstract: Form July 2015 to June 2016, time budget and diurnal activity rhythm of Anastomus oscitans in Mengzi, Yunnan province were studied by instantaneous scan methods. The possibility of adaptability and spread of A.oscitans was analyzed. The results showed that the resting was the main behavior type of A.oscitans during the daytime with the proportion of 61.2% in time budget, while the foraging was only 18.6%. The time budget of rest behavior preening, moving and others was 12.2%, 7.8% and 0.2%, respectively.There was a significant difference in activity rhythm among seasons. The season with the highest percentage of foraging was spring, followed by winter, autumn and summer. In the daily rhythm of behavior, A.oscitans had the highest percentage of foraging in the morning and in the evening, and the lowest at noon, while vice versa in the resting behavior. There was a high and negative correlation between the time budget of foraging and resting. Compared with the study of A.oscitans in original distribution area, the foraging time was significantly lower in China than that in India. This study enriched the biological data of A.oscitans in China and provided a basis for the scientific management of this new species.