The application discloses a training method and a decoding method of a single-time spatial-
temporal filter based on double-frequency
intermodulation, and the training method comprises the following steps: displaying a plurality of training targets in a row-column distribution on a visual stimulation interface, wherein each training target is jointly coded by a first stimulation
signal and a second stimulation
signal; collecting single-time training data of a subject; pre-
processing the single-time training data to obtain ; performing time-domain displacement
processing on the pre-processed mean template of the training target to obtain a time-shifted template; integrating the pre-processed mean template and the time-shifted template of the plurality of training targets to obtain a training target matrix; obtaining a standard reference
signal of the training target, wherein the standard reference signal comprises a double-frequency
intermodulation component; obtaining a training target reference signal matrix according to the standard reference signal; and obtaining a first spatial-
temporal filter according to the training target reference signal matrix. The application achieves the technical effect that a spatial-
temporal filter with good performance is obtained by using single-time training data, and provides a new method for efficient encoding and decoding of a large-instruction-set visual evoked brain-computer interface.