对马尾松（Pinus massoniana Lamb.）与阔叶树檫木〔Sassafras tzumu （Hemsl.） Hemsl.〕、香樟〔Cinnamomum camphora （Linn.） Presl〕和香椿〔Toona sinensis （A. Juss.） Roem.〕的单一凋落叶及31种混合凋落叶分解75、249、437和618 d的纤维二糖水解酶、β-葡萄糖苷酶、多酚氧化酶和过氧化物酶活性进行比较，并对混合凋落叶分解过程中上述酶活性进行混合效应分析和多元线性逐步回归分析。结果表明：总体来看，随着分解时间延长，混合凋落叶的过氧化物酶活性先降低后升高再降低，最低值多出现在分解249 d；其余酶活性则先降低后升高，最低值多出现在分解249或437 d。多数混合凋落叶的酶活性低于单一马尾松凋落叶；2个树种的混合凋落叶中，马尾松和香椿混合凋落叶的纤维二糖水解酶和β-葡萄糖苷酶活性最高，但多酚氧化酶和过氧化物酶活性却最低；3个树种的混合凋落叶中，马尾松、檫木和香樟混合凋落叶的纤维二糖水解酶和β-葡萄糖苷酶活性最低，但多酚氧化酶和过氧化物酶活性却最高。纤维二糖水解酶、β-葡萄糖苷酶、多酚氧化酶和过氧化物酶活性分别在质量比6∶1∶1∶2、6∶1∶2∶1、6∶3∶1和8∶2的混合凋落叶中最高。实验期间，混合凋落叶的4种酶活性以加和效应为主，仅少部分混合凋落叶的酶活性表现为非加和效应。其中，酶活性在分解75 d表现为拮抗效应的混合凋落叶相对较多，而表现为协同效应的混合凋落叶相对较少。分析结果表明：混合凋落叶的初始质量及pH值和含水量对不同分解时间酶活性的影响存在明显差异，部分因子在不同分解时间对同一酶活性的影响甚至完全相反。研究结果显示：混合香椿凋落叶有利于提高纤维二糖水解酶和β-葡萄糖苷酶活性，而混合檫木和香樟凋落叶有利于提高多酚氧化酶和过氧化物酶活性。马尾松与阔叶树凋落叶质量比6∶4有利于混合凋落叶中碳循环相关酶活性的提高。

 Activities of cellobiohydrolase， β-glucosidase， polyphenol oxidase and peroxidase of single leaf litters and 31 mixed leaf litters of Pinus massoniana Lamb. and broad-leaved tree species of Sassafras tzumu （Hemsl.） Hemsl.， Toona sinensis （A. Juss.） Roem. and Cinnamomum camphora （Linn.） Presl at decomposition of 75， 249， 437 and 618 d were compared， and mixed effect analysis and multiple linear stepwise regression analysis were performed on above enzyme activities during decomposition period of mixed leaf litters. The results show that， in general， with the elongation of decomposition time， peroxidase activity of mixed leaf litters first decreases and then increases and finally decreases， and the lowest value mostly appears at decomposition of 249 d， activities of other enzymes first decrease and then increase， and the lowest values mostly appear at decomposition of 249 or 437 d. Enzyme activities of most mixed leaf litters are lower than those of single leaf litters of P. massoniana； among mixed leaf litters of two tree species， activities of cellobiohydrolase and β-glucosidase of mixed leaf litters of P. massoniana and T. sinensis are the highest， but those of polyphenol oxidase and peroxidase are the lowest； among mixed leaf litters of three tree species， activities of cellobiohydrolase and β-glucosidase of mixed leaf litters of P. massoniana， S. tzumu and C. camphora are the lowest， but those of polyphenol oxidase and peroxidase are the highest. Activities of cellobiohydrolase， β-glucosidase， polyphenol oxidase and peroxidase of mixed leaf litters are the highest when mass ratios of 6∶1∶1∶2， 6∶1∶2∶1， 6∶3∶1 and 8∶2， respectively. During the experimental period， four enzyme activities of 31 test mixed leaf litters mainly show additive effect， only enzyme activities of a few mixed leaf litters show non-additive effect. In which， enzyme activities of many mixed leaf litters show antagonistic effect at decomposition of 75 d， while a few mixed leaf litters show synergistic effect. The analysis result shows that there are evident differences in effects of initial quality， pH value and water content of mixed leaf litters on enzyme activities at different decomposition times， and effects of some factors on the same enzyme activity at different decomposition times are even totally opposite. It is suggested that mixed with T. sinensis leaf litter is beneficial to elevate cellobiohydrolase and β-glucosidase activities， while mixed with S. tzumu and C. camphora leaf litters is beneficial to elevate polyphenol oxidase and peroxidase activities. The mass ratio of 6∶4 of leaf litters of P. massoniana and broad-leaved trees is beneficial to elevate activities of carbon cycle-related enzymes in mixed leaf litters.