【Background】Environmental safety assessment of transgenic crop is required before its commercial cultivation. The survival competitiveness assessments of transgenic crop in non-cultivated land is one of the most important methods currently used to ensure safety once commercialized. 【Method】Three experiment materials were put in trial, including transgenic (Bn-csRRM2) high-yield cotton, which was the observed species, and the receptor variety CCRI 12 and transgenic (Bt+CpTI) insect-resistant cotton CCRI 79, which were the check test varieties. The three materials were seeded on the earth′s surface and under 3 cm depth of the earth in late April and late May. We compared the growth indexes among cotton varieties for each month from April to September, including survival rate, plant height, stem diameter, sympodial branch number, and bud and boll number, in order to testing and evaluating their survival competitiveness in non-cultivated land and the risk of weediness. 【Result】Cotton growing in non-cultivated land was weak and stunted with slow and retarded growth. Plants sowing in late April were weak, and there was no boll until late September. Only a very few cottons sowing in late May could produce a few small bolls without cracked boll. 【Conclusion and significance】Transgenic high-yield cotton has no competitive advantage and reproductive capacity, and then no weediness potential. This study could make help for the assessment of environment safety of transgenic cotton.