Plant height and spike shape are important agronomic traits of wheat, which are closely related to wheat yield. The mutant m151 that showing dwarf and compact spike phenotype is obtained by ethyl methanesulfonate (EMS) mutation of wheat variety YZ4110. Genetic analysis of plant height and spike shape of BC2F2:3 population indicated that the dwarf and compact spike traits were controlled by a single incomplete dominant gene. Through the combination of BSA and RNAseq technology and the optimizing the SNP screening method, a candidate causal SNP caused by a mutation from C to T was identified in the 3' end of Q gene on chromosome 5A. This SNP was located in MiRNA172 binding region and different from that of the reported sites of q gene mutants, therefore this site is a new variation in the Q gene. Further study showed that the expression of q gene was highly increased in mutant, which is consistent with results reported in other q gene mutants. The identification of this new mutant site in q gene will deepen our understanding of this important domestication gene and its regulation on regulation of wheat growth and development.