Abstract: To construct Malus sieversii（Ledeb.）Roem. core collection，based on 15 agrinomic traits data and molecular maker from M. sieversii primary core collection，a serials of subsets were sampled at 50% proportion by different genetic distances，respectively. The genetic variation among collections was compared by evaluating the MD（mean difference percentage），VD（variance difference percentage），CR（coincidence rate of range），VR（changeable rate of coefficient of variation）of agrinomic traits and the p（percentage of polymorphic loci），M_Ne（average effective number of alleles），M_I（average Shannon’s information index）and M_PIC（average polymorphism information content）of molecular marker information. The results showed that the core collection constructed on the basis of a combination of data for agrinomic traits and molecular marker data is more representative than that constructed on the basis of data from agrinomic traits or molecular marker data alone. The value of VD，CR，VR，p，M_Ne，M_PIC and M_Iis 50%，96.56%，117.98%，97.67%，97.15%，101.88% and 100.44%，respectively. The mixed genetic distance（D_mix）is more preferable to construct core collection. The core collection was evaluated by using 15 agrinomic traits，and the data showed that it retained more than 93% agrinomic traits and could highly represent the genetic diversity of the initial collection of 300 Malus sieversii accessions.

Key words: Malus sieversii, core collection, agronomic trait, molecular marker