Abstract: In confined poultry buildings, the thermal insulation performance of poultry building construction can have positive impacts on the housing comfortable temperature environment. The ceiling as the main part of poultry house building envelope receives the most radiant heat under high solar insolation. Stronger convection heat transfer between roof inner surface and air increased temperature variations along vertical directions in poultry houses, and higher temperature occurs near the roof of poultry house, resulting in heat stress for the birds near the ceiling. Heat stress usually negatively influences the poultry health, welfare of layers and their production performance. Heat stress has resulted in significant economic losses in large-scale egg productions due to the decrease of egg production rate, the increase of hen mortality and the cost of thermal environment control. Experiments were conducted in 2 poultry houses with different roof types, to determine the effects of roof insulation on thermal environment of poultry houses and egg production rate in hot weather. And the relationship between the roof input cost and the economic benefits of the egg production was discussed. The results showed that: 1) Temperature and humidity fluctuations in experimental poultry house were smaller than that in control poultry house, and temperature in control poultry house was 2.3 ℃ higher than that in experimental poultry house. Temperature was in vertical distribution on the space, and the temperature rose gradually from the ground to the roof. At the height of 3.2 m above the ground air temperature difference was significant (P<0.01), and the vertical temperature difference was greater than 3 ℃. The air temperature also showed vertical distribution in experimental house, but the air temperature difference was not significant at the altitude of 1.6, 2.4 and 3.2 m (P>0.05). 2) Heat stress degree in control poultry house was serious than that in experimental poultry house, and the normal level of temperature and humid in the former was lower by 15.7% compared with that in the latter, alert level was higher by 12.1%, danger level was higher by 1.7% and emergency level was higher by 0.9%. There was no emergency heat stress in experiment poultry house. But the control poultry house was suffered from different degrees of heat stress, and the emergency thermal stress accounted for 2.5% at the altitude of 3.2 m. 3) The average egg production rates in control poultry house and experimental poultry house were 92.5% and 94.0%, respectively, and the average egg weight in control poultry house was 1.9 g less than that in experimental poultry house. Egg production rate at the 3.2 m level was significantly reduced to various degrees compared with the level of 0.8, 1.6 and 2.4 m, respectively (P<0.01), and the mortality rate was very significantly different (P<0.05). There was significant difference of average egg weight between bottom level and other levels (P<0.01), but no significant difference of broken egg rate (P>0.05), and at the bottom level, there was the highest average egg weight. 4) The peak cooling load in control poultry house roof was 2.1 times that in experimental poultry house roof, and the temperature of roof inner surface in the former was 3 ℃ higher than that in the latter. The period of recovery of input cost was 1-1.5 years with insulated roof of experimental poultry house, effectively raising the income of the farmers. This study is expected to provide the theory basis for environmental control and energy saving measures.