We experimentally demonstrate N2^＋ lasing actions at the wavelengths of 353.3, 353.8, and 354.9 nm using a circularly polarized femtosecond laser. The three laser lines correspond to the B2∑u^＋（v＇ = 5, 4, 3） → X2∑g^＋（v = 4, 3, 2） transitions, respectively. Particularly, we reveal the pressure-dependent gain dynamics of these lasing actions from highly excited vibrational states with a pump-probe scheme. Our experimental results confirm that electron eollisional excitation plays an important role in the establishment of a population inversion of N2^＋ lasing at these wavelengths.
