Abstract: 【Objective】 Cloning and spatiotemporal expression pattern analysis of the FT gene （SmFT） of pitaya flower formation were conducted to provide theoretical basis for artificial supplementary light induction of pitaya flower formation and breeding of new light-insensitive pitaya varieties. 【Method】 The red-fleshed pitaya Jindu 1 was selected as the research object to clone the SmFT gene ，which was then performed bioinformatics analysis on. The expression patterns of the SmFT gene in different tissues of pitaya and under the induction of supplementary light at different wavelengths were detected by real-time fluorescence quantitative PCR. 【Result】 The open reading frame（ORF）of SmFT gene was 528 bp and encoded 175 amino acid residues. Bioinformatics analysis showed that SmFT protein was an unstable hydrophilic protein with alkalinity，belonging to non-secretory protein and non-membrane protein. Subcellular localization predicted that SmFT protein was highly likely to be localized in cytoplasm，chloroplast and nucleus. SmFT protein contained a conserved PEBP domain and was closely related to homologous proteins of Vitis vinifera，Vitis serrata and Gypsophila paniculata，while distantly related to homologous proteins of Oxybasis rubra，Chenopodium ficifolium and Amaranthus tricolor. Real-time fluorescence quantitative PCR analysis showed that SmFT gene had obvious tissue expression specificity. The relative expression level of SmFT gene in pitaya calyx was significantly higher than that in other tissues，and was as 15.25 times as that in tender floral buds，2.75 times as that in stem tissues adjacent to tender floral buds （P<0.05），and 2.24 times as that in stem buds. The relative expression level of SmFT gene was higher in the stems and stem buds near the tender floral buds of pitaya，while lower in the mature peel，mature flesh，roots and mature stems， and almost not expressed in the mature stems. With the extension of supplementary lighting days，the relative expression of SmFT gene showed a trend of increasing first and then decreasing under the induction of light quality of different wavelengths，and reached the peak value after 43 d of light induction，and dropped sharply after 50 d（bud stage）. The relative expression level of SmFT gene was the highest under the induction of red light with a wavelength of 660 nm，followed by red light of 630 nm and yellow light of 590 nm，and was the lowest under blue light of 450 nm. 【Conclusion】 SmFT gene has obvious tissue expression specificity and expression differences induced by light of various wavelengths. It is speculated that SmFT may be involved in the early floral bud differentiation induction and the later developmental regulation of floral organs or stems，and play an important role in the floral initiation process of pitaya.