Abstract: For analysis on the heterosis and combining ability among transgenic cotton sterile lines. The crosses were made by using transgenic BT cotton Sterile Lines, to analysis high paternal heterosis, competitive heterosis and combining ability effects for 9 characters. The results showed that the heterosis for yield properties were obvious. The high parent heterosis of seed cotton yield, with an average 19.44%, and 22 crosses has positive heterosis. The competitive heterosis of the trait, with an average -8.36%, and 16 crosses has positive heterosis. High heterosis of boll number per plant was observed among other yield traits. A1, A4 of the female, B5 of the male were good parents with high generic combining ability for most of characters, while A1×B6 and A3×B3 were good crosses whit high SCA for most of traits.