In this research, flow field, heat transfer and mass transfer in a batch fluidized bed dryer, with specific dimensions have been investigated numerically. Drying gas is hot dry gas and the solid particles are unporous and wet. The flow in dryer is assumed two dimensional, axisymmetric, turbulent, incompressible and unsteady. In order to modeling the system, a combination of Eulerian-Eulerian and Eulerian-Lagrangian approaches, have been applied. The drying gas has uniform velocity and temperature profiles in the inlet of the dyer. The atmospheric conditions exist in the outlet of the dryer and wall of the dryer assumed to be adiabatic. Equations of the model are solved with appropriate boundary conditions and time step, for optimized network, using the finite difference numerical method based on control volume. In order to prove the accuracy of the solving method, the problem is simulated in a specific case and the results are compared with available experimental data. The comparison shows a good agreement. The effects of gas inlet velocity, particles diameter, particles density and bed depth, on flow field, and the effects of gas inlet velocity, gas inlet temperature and solid particles initial moisture, on heat transfer and mass transfer field have been investigated. Results indicate that the bed expansion ratio, increases with increasing in the velocity and the bubbles form near the wall. The bed expansion ratio, decreases with increasing in the solid particles diameter and the bubbles form in the center of the bed. The bed expansion ratio, increases with decreasing in the solid particles density and the bubbles form near the wall. Also, the region of the bed which has not any significant change increases. The bed expansion ratio, decreases with increasing in the bed depth. The evaporation rate, increases with increasing in the velocity, gas temperature and solid particles initial moisture and finally, the higher temperature drop occurs in the gas with increasing in the velocity, decreasing in the gas temperature and increasing in the solid particles initial moisture.