The invention provides a data collection device and method of a nuclear power station, and belongs to the technical field of instruction control equipment of the nuclear power station. The device comprises a system control layer and a monitoring control layer; the system control layer is provided with a data collection unit and a controller unit; the data collection unit comprises data input/output interfaces, and the data input/output interfaces communicate with the controller unit via network communication board cards; logic operation is carried out on data collected by the network communication board cards according to a predetermined algorithm in the controller unit; the monitoring control layer is provided with a clock calibrating source; and time of the network communication board cards is calibrated by the controller unit, and the network communication board cards marks data transmitted via data channels connected with the data input/output interfaces with labels. A three-layer configuration including the controller unit, the network communication board cards and input/output interfaces is used, the network communication board cards marks the collected data with labels, so that the processing speed of the controller unit can be improved under the condition that the capacity of the instruction control equipment is not reduced.