Ground penetrating radar (GPR) is a useful tool for railroad track inspection. The use of GPR in the analysis of railroad track condition is desirable since it provides a cost-effective method to examine ballast conditions without digging. However, there is a big challenge for the application of GPR to the railway ballast layers because the relatively large regions of void space in the layer would cause radar signal scattering and make the detection results unreliable. In this study, an improved GPR data processing method for railroad ballast inspection was proposed. A basic set of digital filters was designed to clean up the scan data generated by the radar, and a primary graphical user interface (GUI) was developed for GPR technology to assess the railroad ballast conditions. The lab tests were performed to evaluate the GUI and algorithms proposed in this research. The results indicated that the data processing method was sufficient to detect the ballast layer.