Because　of　its　limited　light　field　mode　and　high　Q　value,　the　whispering-gallery-mode　(WGM)　cavity　has　been　widely　studied.　In　this　study,　we　propose　a　simple,　rapid,　low-cost　and　no-manufacturing　technology　method　that　we　call　the　drip-coating　method　to　obtain　an　irregular　cavity　with　arbitrary　boundaries.　By　using　polyvinyl　alcohol　(PVA)　solution　doped　with　rhodamine　6G,　the　irregular　cavity　with　arbitrary　boundaries　was　drip-coated　on　a　high-reflection　mirror,　forming　a　WGM　laser.　The　sample　was　pumped　with　a　532　nm　pulsed　laser,　and　the　single-mode　WGM　and　multi-WGM　lasing　were　obtained.　All　WGMs　are　the　vertical　oscillation　modes,　which　originate　from　both　the　total　internal　reflection　of　the　PVA/air　interface　and　vertical　reflection　of　the　PVA/mirror　interface.　The　other　boundaries　of　the　cavity　were　not　involved　in　the　reflection　and　could　have　any　shape.　The　mechanism　of　producing　single-mode　lasing　is　due　to　the　action　of　the　loss-gain　cavity.　Multi-WGM　lasing　is　attributed　to　at　least　two　groups　of　different　WGMs　existing　in　an　irregular　cavity.　This　can　be　confirmed　by　using　a　microsphere　model　and　intensity　correlation　method.　These　results　may　provide　an　alternative　for　the　design　of　WGM　lasers.