NOVELTY - Predicting hydrothermal coke yield comprises (i) carrying out hydrothermal carbonization experiment on biomass, (ii) carrying out vacuum filtering separation on solid-liquid product obtained in the step (i), and calculating to obtain hydrothermal coke yield X by the ratio of hydrothermal coke and raw material dry basis mass; (iii) simulating a calculation result by combining with a parallel first-order hydrothermal reaction dynamical model of the hemicellulose, cellulose and lignin, and (iv) carrying model verification by enabling the calculation result of the verified prediction model.    USE - The method is useful for predicting hydrothermal coke yield (claimed).    ADVANTAGE - The method can predict hydrothermal carbonization hydrothermal coke yield of lignocellulosic biomass.    DETAILED DESCRIPTION - Predicting hydrothermal coke yield comprises (i) carrying out hydrothermal carbonization experiment on biomass by adding biomass and water according to mass ratio of 1:5-1:15 into a high-temperature high-pressure reaction kettle, sealing the reaction kettle, heating from room temperature to 225-255 degrees C, reacting for 10-20 hours, after the completion of the reaction, passing cooling water, and rapidly cooled to room temperature to obtain a solid-liquid product, (ii) carrying out vacuum filtering separation on the solid-liquid product obtained in the step (i) to obtain aqueous hot coke, drying the aqueous hot coke, and calculating to obtain hydrothermal coke yield X by the ratio of hydrothermal coke dry basis mass and raw material dry basis mass, (iii) measuring the mass percent of raw materials including hemicellulose, cellulose, lignin and ash, on the basis of hydrothermal carbonization experiment data and the relationship of the mass percentage composition of the hemicellulose, the cellulose, the lignin and the ash content of the biomass, simulating a calculation result by combining with a parallel first-order hydrothermal reaction dynamical model of the hemicellulose, the cellulose and the lignin, and establishing a biomass hydrothermal carbonization hydrothermal coke yield prediction model as follows: X is equal to (aHe+bC+eL+fA)x 100%, where X is hydrothermal coke yield predictive value, and He, C, L and A are respectively quality of hemicellulose, cellulose, lignin and ash, and (iv) carrying model verification: based on biomass feedstock properties, biomass quantity and water amount, carrying out hydrothermal carbonization reaction for 10-20 hours by varying the reaction temperature, measuring the biomass hydrothermal coke yield, combining with cellulose, hemicellulose, lignin and ash parallel to hydrothermal reaction kinetic model simulation, subjecting hydrothermal coke yield prediction model to checking analysis, and enabling the calculation result of the verified prediction model to more approach to experiment data practically measured by a biomass hydrothermal carbonization experiment.