Abstract: The electric current of ex-core detector can be obtained from the scalar product of the spatial weighting function and the core power distribution. In this paper, the transportation calculation code DORT was used to evaluate spatial weighting function of the ex-core detector in two-dimensional geometry, and the cross sections were generated with the nuclear data library MATXS-47, which is processed from ENDF/B-Ⅶ.1. Applying the method to the Indian Point 2, the radial spatial weighting functions were calculated. The calculation results agree well with the reference values.