The invention relates to a data transmission method, in particular to a data transmission method without physical network connection between a power supply SCADA and a traction power supply productionmanagement information system. The invention provides a data transmission method without physical network connection between a power supply SCADA (Supervisory Control and Data Acquisition) and a traction power supply production management information system in order to solve the problem that real-time data transmission cannot be realized in the process of virus transmission and data transmissionof a mobile storage medium. The method comprises the following steps: converting data into a text in a specific coding format through acquired telemetry, telesignalling and other data, partitioning the data, photographing, identifying images, verifying and decompressing the data by adopting a cyclic redundancy check (CRC) algorithm, decrypting the data into real data, finally acquiring control information for displaying data transmission completion, and the like. The method is applied to the field of data transmission without physical network connection.