14-01E

We consider the spin-1/2 Heisenberg model on a simple cubic lattice with ferromagnetic or antiferromagnetic nearest-neighbor interaction within the spin-rotation-invariant second-order Green-function method. We focus on the high-temperature behavior of the static susceptibility which can be used to determine the critical temperature of the model. We compare the Green-function results with the quantum Monte Carlo simulation data. We discuss perspectives for application of the Green-function method for the study of the high-temperature properties of frustrated quantum spin models.