The invention discloses a fermentation process quality prediction method based on dicaryon multiway partial least squares of characteristic space, belongs to both the field of biological fermentation and the field of information science, and particularly relates to a method for predicting quality variables which are difficultly acquired in time when online measurement is conducted in the fermentation process. The method includes the specific steps that training data are acquired, unfolded and standardized, characteristic extraction is conducted on the standardized measurement data and quality data in nuclear space, and the extracted characteristic space is used as the reference for high-dimensional projection; a partial least square model is built, real-time data are acquired to predict projections of the quality data in the high-dimensional space, and the quality data in the high-dimensional space are processed into real prediction values. The method reduces the degree of nonlinearity of the whole model, improves prediction accuracy of the model, and has significance in achieving quality prediction, control and optimal control of the fermentation process.