Abstract: To efficiently cultivate large-diameter Chinese fir timber,24-year-old nearly mature stands and 31-year-old mature stands were selected as research subjects,an L₁₆(4⁴)orthogonal design was adopted,setting four levels for four nutrient elements(N,P,K and Zn).The effects of different formula fertilization treatments on the nearly mature and mature stands were studied,and the optimal fertilization formula and application rate were selected.The results showed that the influence of nutrient elements on the growth of Cunninghamia lanceolata exhibited stand-age heterogeneity:for tree height,the influence order was N>P>K>Zn in nearly mature stands and N>K>P>Zn in mature stands;for DBH,the order was P>K>N>Zn in both stand types;for individual tree volume,the orders were N>P>K>Zn(nearly mature stands)and P>N>K>Zn(mature stands).The optimal fertilization formula for nearly mature stands was application rates of 380,900,390 and 9 g·tree^-1 for N,P,K and Zn fertilizers,respectively,with an optimal nutrient ratio(N∶P₂O₅∶K₂O∶Zn)of 1∶0.62∶1.34∶0.01.The optimal fertilization formula for mature stands was N₃P₃K₃Zn₃,corresponding to application rates of 600,750,300 and 9 g·tree^-1,with an optimal nutrient ratio of 1∶0.33∶0.65∶0.01.Compared to the no-fertilization control(CK),formula fertilization significantly promoted the growth of tree height,diameter at breast height(DBH),and individual tree volume in both nearly mature and mature stands(P<0.01),with a greater fertilization effect observed in the nearly mature stands.Fertilization improved soil fertility in the nearly mature stands;treatment 13(N₂P₂K₂Zn₂)significantly increased the levels of soil C,N,P and K.The difference of soil nutrient indexes between mature forest and CK was not significant.This study provides the basis for the fertilization formula of high efficiency cultivation of large diameter timber of Cunninghamia lanceolata in nearly mature and mature forest.