Abstract: 【Objectives】The aim of this study was to screen for the best growing matrix formulation for tobacco seedling growth,and to provide a theoretical basis for reducing the use of peat for floating tobacco seedlings and improving the recycling of livestock and poultry manure in plateau pastoral areas.【Method】The composite matrix was formed from decayed sheep manure,peat and rice husk,with the addition of some perlite.In this paper,peat was used as a control to study the physical and chemical properties of 9kinds of compound matrices and their effects on the physiological indicators of tobacco seedlings.The 9kinds of compound matrices were:T₁ formula（sheep manure∶peat∶rice husk∶perlite=2∶3∶0.5∶1）,T₂ formula（sheep manure:peat∶rice husk∶perlite=2∶4∶0.75∶2）,T₃ formula （sheep manure∶peat∶rice husk∶perlite=2∶5∶1∶3）,T₄ formula （sheep manure∶peat∶rice husk∶perlite=3∶3∶0.75∶3）,and T₅ formula （sheep manure∶peat∶rice husk∶perlite=3∶4∶1∶1）,T₆ formula（sheep manure∶peat char∶rice husk∶perlite=3:5∶0.5∶2）,T₇ formula （sheep manure∶peat∶rice husk∶perlite=4∶3∶1∶2）,T₈ formula （sheep manure∶peat∶rice husk∶perlite=4∶4∶0.5∶3）,and T₉ formula （sheep manure∶peat∶rice husk∶perlite=4∶5∶0.75∶1）.The Principal Component Analysis method was used to comprehensively evaluate and select the best matrix ratio suitable for growing tobacco seedlings.【Result】The bulk density,total porosity,pH and EC values of T₂ formula were0.24 g/cm~3,70.34%,6.08 and 433μS/cm,respectively,which were in line with the standard of tobacco floating seedling rearing matrix,and the seedling emergence rate was 93.63%.In this study,principal component analysis was used to comprehensively score the growth and physiological indicators,of which T₂（5.132 5） was the highest.【Conclusion】The composite substrate （T₂） with the mass ratio of decayed sheep manure∶peat∶rice husk∶perlite of 2∶4∶0.75∶2 can be used as seedling substrate of tobacco seedling hole plate,and replace some peat tobacco seedling substrate.