Abstract: The （10,6）,（11,7）,（12,8）bands of the first positive band B³∏_g～A³∑_u⁺ of N₂ are analyzed via Zeeman-modulation Magnetic-Rotation Spestroscopy in the range of 17079～17407cm^-1 .Near 900 spectral lines are labeled,including P₁₃ 、Q₁₃ 、R₁₃ and P₃₁ 、Q₃₁ 、R₃₁ branches which have scarcely been observed before,and the improved molecular rotation constants for v=6,7,8 levels of A state and for the v=10,11,12 levels of B state have been obtained by the means of the nonlinear least squares fitting.