AIM: To develop and validate an ELISA method for the determination of secukinumab (SEC) in human plasma and apply it in psoriasis patients. METHODS: A double-antibody sandwich ELISA was developed using anti-secukinumab antibody as the capture antibody and biotin-labeled anti-secukinumab antibody as the detection antibody. The method was systematically validated. Nineteen patients with Psoriasis treated with standard dose of SEC were included. In order to determine trough concentrations of SEC, steady-state blood samples were collected after 24 weeks of treatment. Psoriasis area and severity index score was used to evaluate the response. RESULTS: The SEC concentration showed a good concentration-response relationship within the range of 1.25 to 80.00 μg/mL.The intra-batch and inter-batch precision and accuracy were ≤ 15.00%, and there was no hook effect in the range of 1.25 to 1 000 μg/mL. The median trough concentrations of 19 patients was 33.56 μg/mL (IQR: 32.55-45.98 μg/mL) with an inter-individual variation of 52.00% for body weight adjusted concentration of SEC. The SEC concentrations were not significantly different between the active group and remission group (P=0.92). CONCLUSION: We developed and validated a method for the determination of SEC, which can be used for therapeutic drug monitoring in patients receiving SEC therapy. However the inter-individual variation is large. Further study is needed to explore the association of SEC levels with clinical response in Psoriasis.