Background: Body size traits as one of the main breeding selection criteria have long since being widely used to monitor cattle growth and evaluate the selection response. Here the volume of body size is indicated by body height (BH), body length (BL), hip height (HH), heart size (HS), abdominal size (AS) and cannon bone size (CS). We performed genome-wide association studies (GWAS) for these traits to a broad spectrum of three growth stages (months 6, 12 and 18 after birth) under three statistical models: single-trait GWAS, multi-trait GWAS and LONG-GWAS. The whole genomic single nucleotide polymorphisms (SNPs) were obtained from the Illumina Bovine HD 770K BeadChip genotype on 1217 individuals. Results: In total, 19, 29, and 10 significant SNPs were identified by the three models, respectively. While 21 genes among in these loci appeared to be promising candidate genes, including SOX2, SNRPD1, RASGEF1B, EFNA5, PTBP1, SNX9, SV2C, PKDCC, SYNDIG1, AKR1E2 and PRIM2 detected by single-trait analyze; SLC37A1, LAP3, PCDH7, MANEA and LHCGR detected by multi-trait analyze; P2RY1, MPZL1, LINGO2, CMIP and WSCD1 detected by LONG-GWAS. Conclusions: Multiple association analysis strategies were performed for six growth traits on each stage. This research could offer valuable insights to further explore the potential mechanism of growth traits in Simmental beef cattle.