The experimental investigation of oscillations arising in boundary layer of plasma jet was performed by the registration of the light radiation from the plasma jet. The linear array of eight photodiodes was used. Photodiodes array was positioned both parallel and perpendicular to the axis of the plasma jet. The evolution of oscillations was characterized by dependencies of the following characteristics on axial coordinate: spectra in various radial positions, radial profiles of basic frequency amplitude, ratios of the second or the third harmonics amplitude to basic frequency amplitude and phase velocities of basic frequency and its harmonics. Dependencies of these quantities on plasma jet parameters were studied. Development of spatial structure of the jet boundary oscillations is shown.