Abstract: With the offspring of 58 halfsib Larix olgensis families and 2 controls at 10 years old in Siping Jilin Province as materials, tree height(H), diameter at breast height (DBH) and volume(V) were investigated and analyzed. Genetic variation parameters among different families were calculated. The results showed that there existed extremely significant difference in all the variance sources among different families in H, DBH and V (P＜001). Thereinto,L48 showed the highest H (540 m) and L56 showed the lowest H(371 m). The largest DBH of families were L64 and L13, which were up to 660 cm for all, the smallest DBH of families was L56 (305 cm).The largest V was L64, whose value was 0012 m3, and the smallest V was L65,whose value was 0003 m3. The variation coefficients of H, DBH and V were 1846%, 3273% and 6157% respectively. The individual heritability ranged from 0103 to 0192, which was at medium level. The genetic gains of H, DBH and V of the selected families (L64, L13, L78, L48, L30 and L14) were 876 %, 1604 % and 3008 %, respectively, which were higher than the control LJ (480%, 842% and 1111%) and the control LS (3822%, 7770% and 21399% ), all these could be used as a selection object of excellent family.