Using　the　technique　of　Microfabrication,　such　as　deep　silicon　dry　etching,　lithography,　etc.　Si-PIN　neutron　detectors　with　porous　microstructure　have　been　successfully　fabricated.　In　order　to　lower　the　leakage　current,　the　key　fabrication　processes,　including　the　Al　windows　opening,　deep　silicon　etching　and　the　porous　side　wall　smoothing,　have　been　optimized.　The　cross-section　morphology　and　current-voltage　characteristics　have　been　measured　to　evaluate　the　microfabrication　processes.　With　the　optimized　conditions　presented　by　the　measurements,　a　neutron　detector　with　a　leakage　current　density　of　2.67Acm(-2)　at　a　bias　of　-20V　is　obtained.　A　preliminary　neutron　irradiation　test　with　Cf-252　neutron　source　has　also　been　carried　out.　The　neutron　irradiation　test　shows　that　the　neutron　detection　efficiency　of　the　microstructured　neutron　detectors　is　almost　3.6　times　higher　than　that　of　the　planar　ones.