The experiment was to explore the effects of the soil layer replacement on growth and soil microorganisms ofreplantedseedlings，and to provide a theoretical basis for the renewal of oldorchard.The experimental site was selected from the 25-year apple orchard soil inMengyin，Laizhou andQixia，and the Malus hupehensisRehd.seedlings and YanFu3/M9T337 apple grafted seedings were taken as thematerial.Two treatments were setup，which wereCK(engraftment ditch of in-situ backfill)andSLR(soil layer replacement).The effects of the soil layer replacement on growth，transpirationrate，net photosyntheticrate，stomatalconductance，intercellular carbon dioxideconcentration，soil microorganisms andsoil cation exchange capacity werestudied.The number of the Fusariumsp.was detected by a real -time quantitative PCRdetectionsystem.The results showed that treatment with SLR significantly promoted the growth of replanted seedlings thanCK.The results of the data of Mengyin in September showed that the number of soil fungi decreased by 28.1% and thenumbers of soil bacteria increased by 38.1% after the upper soil was replaced by the lower soil(MSLRA)；the number of soil fungi decreased by 37.1% and the numbers of soil bacteria increased by 31.3% after the lower soil was replaced by the uppersoil(MSLRB)；the bacterial/fungi ratio of each layer of soil in the three ochards was increasedsignificantly，the gene copy number of four harmful Fusariumsp.was reducedsignificantly，indicating that the structure of soil microbial community wasoptimized；The leaf transpirationrate，net photosynthetic rate and intercellular carbon dioxide concentration wereincreased.At the sametime，the change of soil environment significantly increased the soil cation exchange capacity after the upper soilwas replaced by the lower soil.In conclusion，the soil layer replacement can effectively alleviate the continuous cropping obstacles of aging apple orchards.