The Stark broadening of Balmer lines in a hydrogen plasma produced by induced magnetic field has been investigated. A condenser bank discharging into the coil surrounding the discharge tube, produces an alternating axial magnetic field which ionizes, compresses, and heats the hydrogen in the tube. The working conditions are: initial pressure of hydrogen, 2.0×10-1mm Hg; charging voltage, 20 kV; discharge period, 14 microseconds; maximum current, 165 kA. Profiles of the spectral lines of Hβ and Hγ are studied by the photographic method. These lines are considerably broadened. In the whole luminous stage, the mean half-widths of Hβ and Hγ are 14-16? and 18-19? respectively, corresponding to an ion density of 1.7-2.5×1016cm-3. The experimental profiles agree better with Griem, Kolb, and Shen's theory than with Holtsmark's theory. Photo-electrical measurements show that the profile of Hβ changes with time, accordingly the ion density changes also. At the primary current maximum of the third half-period of discharge, the ion density reaches a peak value of 3.2×1016cm-3 which is 2.2 times the initial density of hydrogen atoms.