Abstract: GNSS data preprocessing plays a crucial role in achieving high-precision navigation, positioning, and attitude applications. However, existing GNSS preprocessing tools and modules face challenges in handling multi-frequency and multi-GNSS observation data. To address this issue, we have developed a GNSS data preprocessing software called (GDPS). GDPS includes modules for data download, format conversion, data editing, quality check and auxiliary tools. The software has been implemented using the PYQT5 tool, which enables a graphical user interface. Experimental tests have demonstrated that the software offers a clear interface, strong interactivity, stable module operation, and comprehensive software functions. Consequently, it effectively caters to the diverse needs of users for preprocessing multi-frequency and multi-GNSS observation data.