Abstract: In order to evaluate indoor environment and animal welfare in the housing of sheep,it is necessary to establish a quantified behavioral data of sheep as feedback. Individual behaviors of the Chinese little fat-tailed sheep in three growth phases (lambs,pregnant and lactating ewes) were observed and recorded on a sheep farm in Inner Mongolia in summer,2003. Data processing showed:(1) Behavioral patterns in duration from observed samples (9 in each group) were made up of: time spent in eating and drinking 29.18%,in rumination 28.37%,in resting 31.51%,in locomotion 10.21%,and in others 0.71% including environmental investigation,being alarmed or startled,and social interaction. Individually behavioral durations of three growth phases showed significant difference in durations with respect to intake and drinking,rumination,resting,and locomotion respectively (Kruskal-Wallis H tests,P<0.001). (2) Results of posture choice of the sheep in different growth phases show that time spent in lying for rumination or resting was significantly more than time spent standing by lambs,pregnant and lactating ewes respectively (Wilcoxon test,P<0.001). (3) The counts data of animal behaviors in three levels of temperature showed that on average 31.3% of individuals were lying for rumination and resting at 21-23 ℃,75% at 25-27 ℃,97.13% at 29-31 ℃ in houses of pregnant ewes. This is a significant effect of temperature on number of pregnant ewes lying on floor of the houses (Friedman test,P<0.05). (4) Our data of counts of the pregnant ewes selecting space in lying on floor in the houses from 12:00 to 17:00 at temperature ranging 27-31 ℃,showed that there was significant differences in individuals selecting between A-zone (places naturally ventilated well and without sun shining) and B-zone (places exposed to the sun) (McNemar test,P<0.0001). Many of the ewes increasing from 66% to 83% selected A-zone,whereas a few of the other ewes decreasing from 31% to 14% selected B-zone during observed period. Our results indicate that the behavioral patterns of sheep in the loose housing systems react to the physiological needs at different growing phases,and to environmental impact factors such as temperature and housing space. The study suggests that to establish a quantitative index profile of the sheep behaviors for a feedback review tool may be helpful to enhance the design of production processes and building layout and environment for loose housing systems.