In this paper, the evolution of laser-induced copper plasma spectrum intensity under magnetic field confinement is studied. The evolution process of plasma spectrum intensity and laser energy effect on spectral enhancement are analyzed. Experimental results show that the atomic spectrum and ion spectrum of copper plasma are enhanced as magnetic field increases. In the spectral intensity evolution plot of Cu I 510.55 nm there appears double peak structure in a time range from 1.2 μs to 5.7 μs. The spectral intensity of Cu I 510.55 nm is significantly enhanced in a space range from 0 mm to 1.4 mm away from the target surface. The spectral enhancement factors of Cu I 510.55 nm and Cu I 515.32 nm monotonically decrease with the laser pulse energy increasing, and the maximum enhancement factors for Cu I 510.55 nm and Cu I 515.32 nm are 11 and 8 respectively at the laser energy 20 mJ. The enhancement mechanism of magnetic confinement plasma spectrum is also discussed.