Abstract:To understand the release rule of lignin in the decomposition process of forest leaf litter, the lignin degradation rate of leaf litter of Pinus massoniana (P), Sassafras tzumu (S), Cinnamomum camphora (C) and Toona sinensis (T) was studied. The results showed that lignin in most of mixed litter was enriched during decomposition. The lignin content in combination of PT and PC was high in the first year, and then decreased. However, the lignin content in combination of PS, PST, PSC, PCT and PSCT were enriched at 0-6, 0-9 and 15-18 months, and decreased at other periods. At all decomposition stages, the degradation rate of lignin in some mixed litters showed synergistic effect rather than additive effect, the synergistic effect was stronger in summer and winter than in other seasons. Besides, the lignin degradation rate of PSCT6121, PSC622, PS64 and PC64 showed a synergistic effect in most decomposition stages (≥ 6/8). Therefore, the mixed leaves of P. massoniana and native broad-leaved trees promoted the degradation of lignin, the degradation of lignin in the leaf litter of P. massoniana plantation could be promoted by proper mixing with native broad-leaved species.