[Objective] To select the mixed forest types with good protection function

in order to provide a theoretical basis for guiding the optimization and upgrading of limestone mountain forests in Shandong Province. [Methodes] We selected 8 different mixed forests of 5-year-old in the typical limestone mountainous area of Shandong Province

and the Platycladus orientalis forest was used as the control. Field investigation was conducted and quantitative analysis methods were used to study the soil improvement and erosion reduction benefit from three aspects: the growth condition of mixed forests stand and benefit of improving soil physicochemical properties

the soil hydrological benefit of forest land and the soil erosion abatement benefit. Totally

13 indexes including canopy density

crown width

tree height

soil bulk density

total porosity

available nitrogen

available phosphorus

available potassium

soil saturated water storage

steady infiltration rate

infiltration time

amount of erosion and thickness of litter layer were selected. The comprehensive evaluation of different mixed forest stands was carried out by analytic hierarchy process (AHP). [Results] The P. orientalis+Melia azedarach mingled forest had the best soil erosion reduction benefit

followed by the P. orientalis+ Robinia pseudoacaia and P. orientalis+Cotinus coggygria mingled forest. [Conclusion] The soil improvement and erosion reduction benefit of mixed forests is better than that of pure forests. The soil improvement and erosion reduction benefit of P. orientalis+M. azedarach

P. orientalis+ R. pseudoacacia and P. orientalis+C. coggygria are the best

which is suitable for limestone mountains.