1. On-line NIR technology can be used to monitor all production process in the chemical industry (from raw materials, process intermediates to finished products) 2. On-line NIR technology can cut labor cost, improve production yield and generate high economic, and safety benefits. It is an important part of the development trend of modern intelligent manufacturing and unmanned workshops. 3. On-line NIR technology is used routinely for the measurement the chemical composition content, moisture, hydroxyl number, acid number, carboxyl, esters, alcohols, aromatics, various molecular contents, etc. It could also measure physical parameters such as viscosity, tensile strength, melt index, gel time, etc. related to the composition content. 4. On-line NIR technology: Measurement accuracy and stability are import. But whether the measurement is accurate or not depends not only to the quality of the instrument itself, but also closely related to the many issues (installation method, spectrum acquisition method, spectrum quality, and the ability to overcome interference). In all  on-line NIR measurements, the experience and support offered by the manufacturer is very important.