The method of enhancing the alignment of N2 molecules by controlling pulse duration of two-pulse laser is proposed. The time-dependent Schrdinger equation of the rigid rotor model of N2 molecule in the two-pulse laser is solved numerically by using the pseudospectral method. The degree of alignment for N2 molecules by laser pulses with different durations is calculated. The results show that the alignment can be optimized by selecting the pulse duration and the delay time between the two pulses.