Abstract: The radiative heat transfer of one-dimensional plane-parallel slabs under radiative equilibrium was investigated by Discrete Ordinate Method (DOM): The selection of angular quadrature schemes, which is very important to the accuracy and calculation time of DOM, was studied. The accuracy of the S_N approximation quadrature scheme, Fiveland's angular quadrature scheme with equal weights F_N and Gauss angular quadrature scheme G_N was analyzed. It shows that the accuracy and computation time of DOM increases with the increase of the order of each quadrature scheme. The accuracy of DOM is different from each other for the three quadrature schemes with the same order and F_N is the best one among them. As a conclusion, F_N is recommended in DOM calculations.