Distributed　feedback　(DFB)　lasers　can　be　achieved　by　spin-coating　semiconductor　polymers　onto　the　top　surface　of　a　photoresist　grating　with　designed　periods.　Optical　pumping　using　lasers　within　the　absorption　spectrum　of　the　polymer　induced　strong　modification　on　the　morphological　distribution　of　the　polymer　film　and　consequently　on　the　spectroscopic　response　of　the　DFB　microcavities.　The　corresponding　modification　processes　resulted　mainly　from　the　pump-laser-induced　cross-linking　of　the　polymer　molecules,　which　led　to　the　reduction　in　both　the　thickness　and　refractive　index　of　the　polymer　layer.　The　location　of　the　polymer　laser　was　lowered　from　the　top　to　the　bottom　surface　of　the　DFB　grating.　Concise　modeling　on　the　angle-resolved　tuning　properties　of　the　output　spectrum　of　the　DFB　microcavity　was　achieved　with　excellent　agreement　with　the　experimental　observation,　which　provided　clear　physical　insights　into　the　operation　mechanisms　of　a　DFB　microcavity.