Abstract: According to different sites，Fraxinus mandshurica and Agnus japonica,F．mandshurica and Larix olgensis mixed forest were planted either 5，8 lines belt-mixing or 10×10 trees plot-mixing for studying mixing effects．The results indicated that：survival rate and growth increment of tree species in mixed forest were increased significantly．The mixing effect of 5 lines belt-mixing had the most significant effect among the several mixing types．in which the productivity of forest land was increased effectively．The next better one is 8 line belt-mixing，10×10 trees plot-mixing was not so effective．

Key words: Fraxinus mandshurica, Alnus japonica, Larix olgensis, Mtxed stand