Analyzes the main features of CPLD, and describes the process that use ARM for data fusion after obtaining a large number of food safety testing signals, and gives principle of CPLD. This system has realized the data fusion processing, and has the performances that easy to operation, high sensitivity, strong data analysis capability, stable output and so on. Improving the performance of system data processing greatly and reducing the development costs effectively, provides an effective method of data processing for food safety testing.