Parameters of intraframework potential function suitable for aluminophosphate-5($AIPO_4-5$) are obtained by the constraint method. Using these parameters, we calculated the stabilization energies and their second derivatives of framework atoms and these values are compared with those of zeolite A. It is found that the oxygen atoms in $AIPO_4-5$ framework are more stable than those of zeolite A and that the aluminum atom is also more stable than that of zeolite A. On the other hand, the phosphorus atom in $AIPO_4-5$ framework, in which the silicon atoms of aluminosilicate are replaced by the phosphorus atom, is less stable than the silicon atom of aluminosilicate framework of dehydrated zeolite A.