Due　to　their　novel　optical　and　optoelectronic　properties,　2D　materials　have　received　increasing　interest　for　optoelectronics　applications.　However,　when　the　width　of　the　channel　layer　decreases　to　the　nanoscale,　the　properties　of　2D　materials　can　be　seriously　influenced　due　to　the　boundary　defects　and　the　approximation　of　physical　dimensions　and　mean　free　path　of　the　electron.　That　brings　many　challenges　to　developing　novel　electronics.　Hence,　researchers　began　to　maintain　their　focus　on　1D　semiconductors　without　boundary　defects　and　surfaces.　Herein,　fibrous　phosphorus,　another　Quasi-1D　layered　semiconducting　phosphorus　allotrope　with　air-stable　low　symmetry,　is　reported.　We　found　the　in-plane　anisotropic　Raman　response　and　excitation　and　exciton　emission　at　room　temperature.　Moreover,　the　raw　materials　of　fibrous　phosphorus　are　nontoxic　and　abundant　on　the　earth.　These　excellent　properties　will　make　it　a　highly　competitive　material　for　future　applications　in　the　optoelectronic　area.