Close-coupling calculations are carried out for cross sections of the single electron capture in collisions of N^q＋（q = 5, 6, 7） ions with helium atoms in the collision velocity range from 0.3 a.u. to 1.8 a.u. The relative importances of the single ionization （SI） to the single capture （SC） are investigated for the N^q＋ （q= 5, 6, 7） projectiles, respectively. The SI/SC cross section ratio for the N7＋ projectile obtained from our calculations is in excellent agreement with the experimental data. The ratio curves also show us distinct behaviours when the charge of the projectile is different. The partial electron capture cross sections for different projectiles indicate that the electron on the target He atom tends to be captured by the projectile into its lower orbital of the outer shell with the decreasing projectile charge.
