This paper presents the traditional methods of GD depth analysis method and also its limitations, and the earlier studies of real-time depth measurement technology. A new method of real-time depth determination by laser technology for GD-OES depth analysis is proposed. The real-time depth measurement system is composed of laser displacement sensor and new designed Grimm-type GD source based on laser measurement method, and the system design and technical principles are described in detail. Sputtering depth measurement signal and element spectrum signal can be synchronously collected by this system. The displacement phenomenon of glow discharge source during real-time sputtering depth measurement process is analyzed. The real-time sputtering depth measurement curve of zinc alloy standard sample was tested by two laser displacement sensors measurement system. The actual value of sputtering depth was obtained by adding the depth measurement curve of sputtering surface and the reference plane curve, and the actual depth result is in line with Dektak8-type surface profilometer.