BackgroundPlant height (PH) and spike compactness (SC) are important agronomic traits that affect yield improvement in wheat crops. The identification of the loci or genes responsible for these traits is thus of great importance for marker-assisted selection in wheat breeding.ResultsIn this study, we used a recombinant inbred line (RIL) population with 139 lines derived from a cross between the mutantRht8-2and the local wheat variety NongDa5181 (ND5181) to construct a high-density genetic linkage map by applying the Wheat 40 K Panel. We identified seven stable QTLs for PH (three) and SC (four) in two environments using the RIL population, and found thatRht8-B1is the causal gene ofqPH2B.1by further genetic mapping, gene cloning and gene editing analyses. Our results also showed that two natural variants from GC to TT in the coding region ofRht8-B1resulted in an amino acid change from G (ND5181) to V (Rht8-2) at the 175thposition, reducing PH by 3.6%~6.2% in the RIL population. Moreover, gene editing analysis suggested that the height of T2generation inRht8-B1edited plants was reduced by 5.6%, and that the impact ofRht8-B1on PH was significantly lower thanRht8-D1. Additionally, analysis of the distribution ofRht8-B1in various wheat resources suggested that theRht8-B1ballele has not been widely utilized in modern wheat breeding.ConclusionsThe combination ofRht8-B1bwith other favorableRhtgenes might be an alternative approach for developing lodging-resistant crops. Our study provides important information for marker-assisted selection in wheat breeding.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-023-04343-3.