OBJECTIVES: To perform a health economics evaluation for insulin injection pen-needle with different lengths in diabetic patients in China. METHODS: With the relationship between HbA level and diabetes-related complications obtained from literature, cost-benefit analysis was applied to evaluate the net cost saving (including the cost of needles and cost of complications and adverse events treatment) of shorter pen-needle compared to the longer one, from the perspective of society. The unit costs were retrieved from published sources and outcomes of the effectiveness were derived from meta-analysis of relevant literatures related to different lengths insulin pen-needle. One-way sensitivity analysis was conducted to demonstrate the robustness of results. RESULTS: The meta-analysis showed that compared to the longer needle, the shorter one decreased HbA by an average of 0.11% and reduced the risk of hypoglycaemic events by 17%. A net saving of $27 per patient based on shorter needle resulted from decreased adverse events, while the costs of needles were increased by $9 during the trial time. If the retinopathy was included, shorter needle produced a net saving of $320 per patient due to decreased complications, and the economic evaluation revealed shorter needle can totally save $338 per patient compared to the longer one. If without retinopathy, the net saving was $129 per patient due to decreased complications, and the totally saving was $147 per patient. Sensitivity analysis showed that the results were stable. CONCLUSIONS: Current findings indicate that shorter insulin injection pen-needle lead to a decreasing of complications and adverse reaction compared to longer needle, and subsequently could lead to a reduction in health costs.