Abstract: Thermal design and thermal testing of Finance Fiscal Cash Register(FFCR) are becoming more difficult because of its miniaturization and confidentiality. For this reason, a thermal design based on heat transfer for PCBA of FFCR is conducted, and Icepak thermal analysis software package is used to carry out numerical simulation of temperature field of PCBA for obtaining temperature distribution of PCBA under the conditions of 4 operating modes model of charging state. The numerical simulation result shows that component temperature of data transfer model is significantly higher than that of other operating modes except the components protected by the wall. Thermal test is carried out to verify thermal design and thermal analysis of PCBA of FFCR. The result shows that component temperature is within its reliability temperature range, the result of numerical simulation is in good agreement with the thermal test result, showing the validity of thermal design and thermal analysis.