To figure out the association between plasma Hcy status and type 1 diabetes mellitus (T1DM). We searched the PubMed Web of Science, and The Cochrane Library to identify eligible studies. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of selected studies. All analyses were performed using the STATA, version 12 software. 15 studies were included in this investigation. Our meta-analysis indicated that plasma Hcy concentrations in T1DM patients without any complications were normal compared with healthy people [13 studies, SMD: -0.08, 95% confidence interval (CI): -0.44 to 0.28, P=0.67]. However, a significant elevation of plasma Hcy concentrations was observed in T1DM patients with only diabetic retinopathy (DR) (5 studies, SMD: 0.34, 95% CI: 0.13 to 0.55, P=0.002), only diabetic nephropathy (DN) (4 studies, SMD: 0.76, 95% CI: 0.18 to 1.33, P=0.01) and both the two complications (3 studies, SMD: 1.05, 95% CI: 0.03 to 2.07, P=0.043) compared with T1DM patients without any complications. Homocysteine levels elevate in T1DM patients with DR and DN, but don't elevate in T1DM without any complications.