Photodetectors　(PDs)　for　weak　light　signal　detection　have　wide　applications　for　optical　communication　and　imaging.　Antimony　sulfide　(Sb2S3)　as　a　nontoxic　and　stable　light-sensitive　material　becomes　a　promising　candidate　for　weak　light　PDs,　which　are　developing　in　the　direction　of　high　response,　high　speed,　and　low　cost.　Herein,　a　self-powered　Sb2S3　PD　with　the　structure　of　FTO/TiO2/Sb2S3/Au　is　developed　to　achieve　weak　light　detection　for　300-750　nm　visible　light.　We　control　the　Sb2S3　thickness　with　about　460　nm　to　match　depletion　region　width　(438　nm)　and　obtain　an　excellent　photoresponsivity　and　3　dB　bandwidth.　Furtherly,　we　prepare　pyramid　structure　polydimethylsiloxane　(PDMS)　on　the　illuminating　surface　to　enhance　the　performance　of　weak　light　detection　by　lighttrapping　effects.　The　photocurrent　of　Sb2S3　PD　with　20　mu　m-sized　PDMS　texture　achieves　13.6%　improvement　compared　with　the　control　one.　Under　weak　530　nm　light　illumination　of　1　mu　W　cm(-2),　the　self-powered　Sb2S3　PD　with　PDMS　achieves　high　responsivity　(3.41　A　W-1),　large　detectivity　(2.84　X　10(13)　Jones),　and　ultrafast　speed　(15　its).　The　present　Sb2S3　PD　and　light-trapping　strategy　are　expected　to　provide　an　alternative　to　future　commercial　weak　light　detection　applications.