Abstract: The secondary flowering Hemerocallis fulva ‘Licheng 6’were used as the material,the method of artificial shading,four photoperiods of natural light CK（14 hours/10 hours）,Ph12（12hours/12hours）,Ph10（10hours/14hours）,and Ph8（8hours/16hours）were set up,the effect of photoperiod on the secondary flower bud differentiation of Hemerocallisfulva ‘Licheng 6’were studied,with a view to elucidating the regulation of the flower bud differentiation process of Hemerocallis fulva ‘Licheng 6’,to provide a better solution for the Hemerocallis fulva flower differentiation,and in order to provide references for the Hemerocallis fulva floral regulation and daylily species cultivation.The results showed that under the natural photoperiod condition,Hemerocallis fulva ‘Licheng 6’entered into reproductive growth normally,Ph12was 15days later than CK,and Ph10and Ph8 were 30days later than CK,and none of the three treatment groups completed the whole process of floral bud differentiation;CK bloomed normally,and Ph12had 3scapes but no bloom,Ph10had 6scapes but no bloom,and Ph10had 6scapes but no bloom.CK bloomed normally,while Ph12scaped 3but did not bloom,Ph10scaped 6but did not bloom,and Ph8scaped 3but did not bloom,indicated that shortening the photoperiod affected the secondary bud differentiation and blooming of Hemerocallis fulva ‘Licheng 6’;under the photoperiod treatment,the soluble sugar content of leaves and roots of the three treatment groups was lower than that of CK,while the starch content was higher than that of CK,indicating that the shortening of the photoperiod delayed the flowering and starch content of Hemerocallis fulva ‘Licheng 6’through affecting soluble sugar and starch and starch content,indicated that shortening the photoperiod slowed down the process of flower bud differentiation by affecting the soluble sugar and starch content.