The present invention provides a field data transmission apparatus, method and system. The apparatus comprises: an analog signal acquisition and conditioning module, an analog-to-digital converter, a control processor and a Profinet interface, wherein the analog signal acquisition and conditioning module is configured to receive field data that is in the form of an analog signal and sent by an external sensor, and send the field data that is in the form of an analog signal to the analog-to-digital converter; the analog-to-digital converter is configured to convert the received field data that is in the form of an analog signal into field data that is in the form of a digital signal and then send the converted field data to the control processor; the control processor is configured to process the received field data that is in the form of a digital signal and then send the processed field data to the Profinet interface; and the Profinet interface is configured to send the received field data that is in the form of a digital signal to an external control end over an industrial Ethernet. The present solution can improve the quality of data transmission.