In order to explore the problem of solving the fire risk of Pinus massoniana,interplanting Altingia gracilipes,Schima superba and Phoebe bournei under the canopy of P.massoniana was tested.After 20 years of stand improvement,the biomass,undergrowth vegetation analysis,canopy structure,microclimate and fire resistance were analyzed,results show that combustible was 37.91±4.55 t/hm ² in P.massoniana,combustible were found in the mixed forests of P.massoniana with A.gracilipes,S.superba,P.bournei,which were 23.71±2.36 t/hm ²、22.54±1.85 t/hm ²、21.58±2.03 t/hm ².The undergrowth vegetation of P.massoniana were Dicranopteris dichotoma and miscellaneous bamboo,while the undergrowth vegetation of mixed forest were dominated by one or two-year-old shady herbs.The spatial structure of P.massoniana were composed of forest canopy,undergrowth vegetation and litter layer,while that of mixed forest were composed of forest canopy,broad-leaved forest canopy,undergrowth vegetation layer and litter layer.The ignition temperature of P.massoniana leaves was lower than that of broad-leaved trees,and the oil content was higher than that of broad-leaved trees.The temperature of P.massoniana were higher than those of mixed forest,and the humidity of P.massoniana were higher than those of mixed forest.When broad-leaved trees were intercropped in P.massoniana,the fire-fighting efficiency was significantly improved.The fire-fighting efficiency ranged from high to low as follows:P.massoniana and A.gracilipes 、P.massoniana and S.superba、P.massoniana and P.bournei、P.massoniana.