Abstract: The purpose of the color scanning digitizing processing system of the precipitation autographic record paper is to realize converting data from color scanning graph to the precipitation intensity per minute. The design thought, framework and functions of the computer processing system are introduced. The master functions of this system include the pretreatment of the precipitation autographic record paper, paper scanning, scan checking-up, precipitation curve collecting and precipitation intensity data conversion. The key technologies in system design causing the reader to all-round know the main content and the characters of this system are also expounded. The representative technologies include the precision analysis and the scan resolution of digitizing the scanning graph, the technique of automatic tracking and collecting the precipitation curves, the technique of data processing of digitizing graph, the synchronous orientation display technique etc. The color scanning digitizing processing system of precipitation autographic record paper has been applied to operations in Provinces.