Objective To systematically evaluate the efficacy and safety of adding alpha-glucosidase inhibitors (AGIs) to insulin therapy in adult patients with type 1 diabetes (T1DM). Methods Articles about randomized or non-randomized controlled trials of insulin combined with AGIs in adult patients with T1DM were retrieved from Chinese and English database. Meta-analyses were performed by using Review Manager 5.3. Results A total of 616 patients were included from 10 clinical trials. Compared with adding placebo or nothing, in terms of efficacy, the addition of AGIs resulted in decreased HbA1c, mean blood glucose, fasting plasma blood glucose and 2-hour postprandial blood glucose levels (all P<0.05). And this scheme improved the glucose variability including mean amplitude of glycemic excursions and the largest amplitude of glycemic excursions (P<0.05, respectively). As to safety, AGIs increased the risk of total adverse reactions (P<0.05), most of them were gastrointestinal complaints, while the occurrence and the frequency of hypoglycemia were similar (P>0.05, respectively). This scheme could also lead to the reduced total daily insulin dose (P<0.05) but had no significant effect on body weight, triglyceride or cholesterol concentration (P>0.05, respectively). Conclusions The addition of AGIs to insulin therapy in adult patients with T1DM may reduce HbA1c and improve the glucose levels and glucose variability. But total adverse effects especially the gastrointestinal complaints should also be considered in the use of AGIs although it does not increase the risk of hypoglycemia.