In view of interaction of fluid flow field and rheology field, the numerical simulation model in pressing of oil plant was developed on the basis of the theory of fluid-solid interaction. The interaction numerical method for the fluid flow field and rheology field was proposed, which adopted finite difference and finite element method. The deformations of rapeseed and rapeseed kernel in pressing were simulated. The distribution and disappearance of pore pressure in rapeseed kernel, and the distribution of effective stress of rapeseed kernel were numerically simulated and predicted. The results indicate that the simulated model and interaction method can simulate the pressing of rapeseed and rapeseed kernel well.