m⁶A modification is one of the most abundant modifications on mRNAs and regulates the fate decisions of mRNAs. YT521B homology (YTH) domaincontaining proteins are typical m⁶A “readers” that recognize and bind m⁶A for posttranscriptional regulation of genes. To investigate the functions of Arabidopsis YTH domaincontaining proteins ECT6 and ECT7 and their molecular mechanisms, we conducted genotyping, semiquantitative PCR identification and flowering phenotype observation of ECT6, ECT7 and ECT6 ECT7 double mutants. Meanwhile, we also analyzed the subcellular localization of ECT6 and ECT7 by cytological observation and detected the expression of key flowering genes by qRTPCR. The results showed that: (1) ECT6 contains five exons and four introns, and the ECT6 mutants is inserted in exons 3 and 5 of the ECT6, respectively; the ECT7 contains six exons and five introns, and the ECT7 mutants is inserted in exons 4 and 6 of the ECT7, respectively. (2) Mutants ECT6 and ECT7 were both lossoffunction mutants, and they both exhibited earlier flowering and reduced leaf number under longday condition. (3) The ECT6 ECT7 double mutant showed earlier flowering and reduced leaf number under both longday and shortday conditions. (4) FLC and FTLC are key flowering regulators. qRTPCR results showed that the expression levels of the flowering repressor gene FLC were reduced and the expression levels of the florigenin gene FTLC were increased in the ECT6 ECT7 double mutants. In addition, the expression levels of the vernalization pathway genes VIN3, VRN2, VRN5 and the autonomous pathway gene FVE were also significantly increased. (5) Both ECT6 and ECT7 were localized in the nucleus and cytoplasm.