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Branching is speculated to contribute to the plant architecture and crop yield. As a quantitative trait, branching is regulated by multiple genes in non-heading Chinese cabbage (NHCC). Several related candidate genes have been discovered in previous studies on the branching of NHCC, but their specific functions and regulatory mechanisms still need to be verified and explored. In this study, we found that the expression of <i>BcHTT4</i>, the ortholog to <i>HEAT-INDUCED TAS1 TARGET4 (HTT4)</i> in <i>Arabidopsis</i>, was significantly different between ‘Suzhouqing’ (common type) and ‘Maertou’ (multiple shoot branching type) in NHCC, which was consistent with the previous transcriptome sequencing results. The silencing of <i>BcHTT4</i> expression in non-heading Chinese cabbage promotes axillary bud growth at the vegetative stage. When <i>BcHTT4</i> is overexpressed in <i>Arabidopsis</i>, branching will decrease. In further study, we found that <i>BcHTT4</i> interacts with immunophilin <i>BcFKBP13</i> in vivo and in vitro through yeast two-hybrid analysis and bimolecular fluorescence complementation (BiFC) assays. Moreover, quantitative real-time PCR analysis showed that when the expression of <i>BcHTT4</i> was silenced in ‘Suzhouqing’, the expression of <i>BcFKBP13</i> also decreased significantly. Our findings reveal that <i>BcHTT4</i> is involved in the branching mechanism and interacts with immunophilin <i>BcFKBP13</i> in NHCC.