The present invention provides a one-dimensional global rainbow measurement device and a measurement method. The measurement device comprises three parts, i.e., a laser emission unit, a signal collection unit and a signal processing unit. The laser emission unit is modulated to be a light sheet by a laser beam emitted by a laser, and configured to irradiate droplets in a spray field to generate rainbow signals. The signal collection unit is configured to separately image, by an optical system unit, the rainbow signals at measurement points of different height onto different row pixels of a CCD signal collector. The signal processing unit is configured to convert the received rainbow signals and process by a computer the rainbow signals in a form of data to obtain the measured values. The present invention can analyze gas-liquid phase flow fields during the injection, realize the online measurement of fuel atomization, spray and other processes, and can measure the refractive index, size, temperature and other parameters of the spray droplets in a real-time and non-contact manner.