The invention discloses a system and a method for monitoring communication among process layers of a digitalized transformer substation. The process layers are provided with a plurality of merging units and a plurality of optional switchboards. For a process layer not configured with a switchboard, each merging unit is provided with at least an information monitoring interface; for a process layer configured with a switchboard, the switchboard is provided with at least one information monitoring interface. The monitoring system comprises at least one information acquisition and pre-analysis device used for capturing and pre-analyzing the sample value message of the process layers; the monitoring system also comprises a monitoring and analyzing device used for analyzing the sample value message off-line in a comprehensive way, each merging unit or each switchboard is connected with the information acquisition and pre-analysis device via the information monitoring interface, and the information acquisition and pre-analysis device is connected with the monitoring and analyzing device. The inventive monitoring system and method can capture and pre-analyze the sample value message of the process layers in real time, thus greatly improving controllability and maintainability of the transmission of the sample value message of the process layers of the digitalized transformer substation.