In order to explore the influence of high temperature in summer on the behavior, thereof weeding effect, and production performance of Wuqin 10 meat ducks under rice-duck symbiosis, five rice fields were selected in this study, which were divided into one large field (T0, 2 hm2) and four small fields (T1-T4, each one was 0.33 hm2). Wuqin 10 meat ducks were placed in above fields, with a density of 105~225 ducks/hm2. The experiment started from June 30th to August 31st. The occurrence and duration time of ducks' swimming, resting, feeding and other behaviors in the field all day, thereof the weeding effect, were continuously observed. The outdoor temperature at 08:00 and 14:00 every day, weekly weight gain of ducks and feed consumption were recorded during the experiment. The results showed that under the condition of high temperature in summer, the activity peaks of ducks in the field were usually at 05:00-10:00 and 15:00-19:00, and at noon, ducks actively sought the shade to enjoy the cool. Ducks generally moved within a certain radius near the duck house, and there was almost no duck activity at the distal region of T0 field far away the duck house. The weeding effect of rice-duck symbiosis was positively correlated with the frequency of ducks' activities in the field, and the frequency of ducks' activities in waterless areas was significantly reduced, so the weeding effect was poor. High temperature can cause heat stress in ducks, which significantly reduces the growth rate. The results showed that Wuqin 10 meat ducks were suitable for the rice-duck symbiosis mode, and its weeding effect was positively correlated with the range of duck activities. The high temperature in summer significantly affected the performance of ducks, and the shading in sports fields, irrigation in paddy fields and ditches could effectively reduce the heat stress.