Abstract: The local homogenization plus the discontinuous factor corrected diffusion method was adopted for the control rod calculation of the pebble bed high temperature gas cooled reactor, and was proven to be effective. But the result for the small absorber ball region with strong absorber is not good enough. The investigation shows that the strong absorber still has a great influence on the flux distribution of the nearby graphite region, which is not capable for normal diffusion method. The improved calculation procedure was proposed, not only to calculate the discontinuous factor of the absorber region, but also to calculate the discontinuity factor of the neighboring graphite region. The numerical result demonstrates that the improved performance and the accuracy of transport calculation based on fine heterogeneous model can be achieved in the diffusion calculation framework.