Abstract: The individuals from the 23^rd generation of Northeast Agricultural University broiler lines divergently selected for abdominal fat content （NEAUHLF） were used in the present study.The feed efficiency related traits and digestive system related traits were determined and compared between fat and lean line broilers.Subsequently,the genetic parameters of feed efficiency related traits and digestive system related traits of fat and lean broilers were estimated.The results showed that the feed conversion rate （FCR）,residual feed intake （RFI）,and duodenal length （DL）,jejunum length （JL） of lean broilers were significantly lower than those of fat broilers （P＜0.05）;the ileum length （IL） and rectal length （RL） of lean broilers were significantly higher than those of fat broilers （P＜0.05）,and other traits were no difference （P＞0.05）.Glutenous stomach weight （GMSW）,JL,and IL were the high heritability traits （0.41≤h~2≤0.45）,and liver weight （LW） and cecum length （CL） were the moderate heritability traits（h~2=0.36,0.35）,DL and RL were the low heritability traits （h~2=0.09,0）.The FCR showed a moderately negative genetic correlation with GMSW and JL （rg=-0.35,-0.37）,a lowly negative genetic correlation with IL and CL （r_g=-0.14,-0.12）,a moderately positive genetic correlation with DL （r_g=0.25） and a lowly positive genetic correlation with LW （r_g=0.07）.The RFI showed a highly negative genetic correlation with GMSW （r_g=-0.46）,a moderately negative genetic correlation with JL （r_g=-0.32）,a lowly negative genetic correlation with IL and CL （r_g=-0.18,-0.10）,a lowly positive genetic correlation with LW and DL（r_g=0.14,0.14）.It was speculated that when breeding improved the feed efficiency of broilers,GMSW,JL,IL,and CL could increase and LW and DL could decrease.The research could provide references for improving the balanced breeding system of broilers.