The generation of ultrashort attosecond pulse requires both an enhanced high harmonic generation and the spectral-phase control. In the present work, an efficient method is theoretically investigated for extending HHG cutoff energy in Br-2 molecule using TDDFT. The effects of molecular orientation and carrier-envelope phase of the laser on the high harmonic spectrum are analyzed. As a result, by the fine modulations of the laser field, the harmonic plateau is enlarged and the position of structure-induced interference minimum shifts. We also provide a physical picture on the intensity dependence of the spectral minima in the harmonic spectra.