In frame of quantum-mechanical approach the microscopic mechanisms and characteristics of deformation and destruction by uniaxial extension of carbon nanotubes (CNT) the different diameters and texture have been investigated. We analyzed CNT (4,4) and (5,5) “recliner” and (8,0) “zigzag” by different regimes of loading. Results of calculation of Young modulus shown that CNT with big diameter (E=1.2 TPa) are more strength than CNT with smaller diameter (E=0.76 TPa). CNT as “recliner” are firmnesses than CNT as “zigzag” (E=0.825 TPa). Thus the computer experiments exhibit as qualitative so quantitative adequacy with well-known from literature experimental data and existing theoretical calculations.