This paper discusses the difference in censtruction betweentwo Chinese wcrd processing system, the environment and method of runninga CCDOS software under the DOS/ C. DOS/ C is one Chinese word processingsystem used in the Chinese terminal of Siemens computer system, comparisonwith the other CCDOS, there are a lot of difference, especially With the Soft-ware running under the CCDOS Used Very currently nowadays.