The　Dendrolimus　punctatus　Walker　is　the　most　serious　forest　defoliator　in　China.　It　is　meaningful　to　effectively　conduct　early　warning　of　Dendrolimus　punctatus　Walker　damage　for　the　forest　sustainable　development　maintenance　and　economic　losses　reduction.　Taking　Fujian　Province　as　the　study　area,　the　materials　of　climate,　topography,　forest　stand,　pest　source　and　human　environment　were　collected.　Relying　on　the　Quantitative　Theory　I,　the　pest　levels　of　Dendrolimus　punctatus　Walker　in　2011　were　simulated.　The　occurrence　probability　of　Dendrolimus　punctatus　Walker　damage　and　its　early　warning　technology　was　built　according　to　the　correspondence　of　occurrence　probability　and　early　warning　grades.　The　results　showed　that　(1)　The　blue　early　warning　(Degree　IV　early　warning)　of　Dendrolimus　punctatus　Walker　damage　should　be　sent　out　when　one　of　the　following　states　can　be　met　in　the　regions　without　occurrence　in　last　year:　Sunshine　hours　higher　in　mid-　December　last　year,　low　elevation,　middle　dense　forest,　sunshine　hours　within　1359-1580　h　last　year,　average　temperature　unusual　higher　in　late　August　last　year,　average　temperature　unusual　lower　in　early　January　this　year　and　sunshine　hours　unusually　lower　in　mid-　December　last　year.　The　corresponding　probabilities　are　12.13%,　10.94%,　10.36%,　10.21%,　10.09%,　10.06%　and　10.00%　respectively;　(2)33　random　samples　of　non-occurrence　in　2010　and　occurrence　in　2011　were　used　to　verify　this　early　warning　technology,　confirming　its　reliability.