The invention discloses an extra-high aluminum anti-radiation heat-resisting ferrite stainless steel alloy material with a low neutron absorption function and a preparation method thereof. The ferrite stainless steel alloy material is prepared from the following major ingredients in percentage by mass: at most 0.03 percent of C, at most 0.02 percent of N, at most 0.01 percent of S, at most 0.02 percent of P, 10.0 to 15.0 percent of Cr, 7.0 to 15.0 percent of Al and the balance of iron and inevitable impurities, wherein the Al content and the Cr content meet the formula requirements that [Al]/[Cr] is greater than or equal to 0.7 but is smaller than or equal to 1.0. After proportioning and vacuum induction melting, casting formation is performed; the processes such as hot forging, pipe penetration, hot rolling, cold rolling and annealing treatment are performed; finally, an extra-high aluminum anti-radiation heat-resisting ferrite stainless steel alloy material pipe or plate with the low neutron absorption function is finally prepared. The defect that the ferrite stainless steel becomes brittle after being used for a long time at 300 to 600 DEG C is effectively overcome; the raw material cost can be greatly reduced.