The　GaN-based　heterostructures　and　related　HEMTs　(High　Electron　Mobility　Transistors)　were　investigated　by　1MeV　neutrons　at　fluences　up　to　10(15)　cm(-2),　yielding　an　increase　of　the　densities　of　screw　dislocations　and　edge　dislocations　for　GaN-based　heterostructures.　It　gave　the　result　that　neutron　irradiation-induced　structural　defects　into　GaN-based　materials,　and　the　irradiation-induced　dislocations　would　propagate　to　the　material　surface　causing　surface　morphology　deterioration.　However,　the　GaN-based　material　strain　was　robust　to　neutrons,　and　the　more　initial　dislocations,　the　easier　to　generate　irradiation　defects　and　thus,　more　strongly　affecting　the　electrical　property　degradations　of　materials　and　devices.　Meanwhile,　the　reduction　of　the　two-dimensional　electron　gas　(2DEG)　concentration　(n(s))　caused　by　irradiation-induced　defects　led　to　the　reducing　the　drain　current.　Moreover,　the　significant　degradation　of　the　reverse　gate　leakage　current　at　fluences　ranging　from　10(14)　to　10(15)　cm(-2)　could　be　attributed　to　the　irradiation-induced　deep　defects.　The　neutron　induced　damage　was　more　difficult　to　anneal　recovery　than　other　particles,　due　to　the　neutron　irradiation-induced　deep　levels　and　defect　complexes　such　as　defect　clusters.