The invention discloses a network data anomaly detection method based on a dendritic cell algorithm, which mainly overcomes the defect of unstable detection rate of the prior art. The method comprises the following steps of: (1) normalizing the text characteristics and value characteristics of KDD99 data; (2) selecting an antigen type and an input signal from the normalized KDD99 data; (3) respectively setting a DC cell population number M, a migration threshold and an antigen threshold of a mature environment from the dendritic cell algorithm; (4) reading data, and performing weight conversion on the input signal; (5) marking the cell environment and presenting the antigen type according to an output signal; (6) calculating the antigen value of the mature environment of the antigen type;and (7) calculating the detection rate and false alarm rate. Compared with the prior art, the method disclosed by the invention improves the stability of the detection rate, further improves the detection rate and reduces the false alarm rate, and can be used for performing anomaly detection on the received data in the network.