The purpose of this study was to explore the effect of backfat thickness (BF) on reproduction performance in Landrace×Yorkshire primiparous sow at different gestation stages under intensive and large-scale feeding management mode. A total of 522 Landrace×Yorkshire primiparous sows with similar weight were selected and bred during the second estrus. The thickness of back fat was measured on the day of insemination,30,60,90,and 110 days after insemination (dai). Then,reproductive performance data such as total number of born (TNB),number of born alive (NBA),number of healthy born (NHB),number of weak born (NWB),number of stillbirths (NS),litter weight at birth (LWB)，weight per piglet (WPP) was recorded. The results showed that maintaining 16-18 mm BF before 60 dai and 18-20 mm BF after 60 dai had a significant role in promoting reproductive performance in Landrace×Yorkshire primiparous sow. When the thickness of BF was＞6 mm during the whole gestation period,TNB and NHB were significantly lower than that of pregnant sows with BF＜2 mm,2-4 mm and 4-6 mm. When the BF was 2-4 mm,NHB was the highest (10.96±2.02),and LWB was the largest. The BF thickness at 110 dai and its growth during the whole pregnancy were negatively correlated with TNB,NBA,and NHB (P＜0.05). Taken together,in actual production,the BF should be maintained at 16-18 mm before 60 dai and 18-20 mm after 60 dai by differentiated feeding program according to BF condition and avoid excessive growth of BF thicker than 6 mm by controlling the feeding volume during the whole gestation,so as to achieve the maximum productivity of the primiparous sows.