In recent years, the rapid laser technology has promoted the development of spectroscopic technology. Various on-line monitoring technologies based on optical detection and spectral retrieval play an irreplaceable role in the field of environmental monitoring with high sensitivity, high resolution, high selectivity, multi-component, real-time and other advantages. The new development of on-line monitoring technology in the field of environmental pollution and environmental security is explored. And some beneficial suggestions about continuous development of science and technology of optical remote sensing application are proposed.