Precipitation is an important investigation object of global hydrothermal circulation and climate change. Data of precipitation particle spectra has important applications in automation identification of present weather, research of cloud structure and correction of weather radar echoes. A system for precipitation observation based on linear image sensor can capture image of precipitation particles, which provides raw data for researches of microphysical characteristics of raindrop. On the basis of a brief introduction of work principle of precipitation particle measurement system based on linear image sensor, the key technology of precipitation particle measurement and linear image data process are discussed. The demand of optical system parameters, high sampling speed of linear image sensor and linear image data process are analyzed separately in order to expect that linear image acquisition technology can be better applied in precipitation particle measurement.