Abstract: The effects of four kinds of photoperiods on the growth of Abies concolor seedlings were studied.The results showed that terminal buds flushed under the extended photoperiod,the average days of bud bursting were 28,26 and 22 days;extended photoperiod could promote the growth and biomass allocation of the Abies concolor seedlings, especially a treatment for 22 hrs got the best results:average height 10.86 cm average root collar diameter 0.32 cm average number of lateral buds and lateral shoots 8 and 7 respectively,total dry weight,shoot and root dry weight and hair roots were all greater than that of CK seedlings.The two provenances used in this study responded differently to the extended photoperiods and in general,provenance No.8 was a little better than No.10.