An inflammatory skin condition that can affect people of all ages is psoriasis. Each population has a different psoriasis prevalence level, ranging from 0.1 to 11.8%. Depending on the severity of the condition, numerous treatment options are available, including topical therapy, phototherapy, systemic therapy, and biological medicines for psoriasis. We reported that a 35-year-old man complained of having thickened and scaly skin across most of his body four months ago. Since seven years ago, the patient has frequently complained of the same illness and has received oral methotrexate and phototherapy. An examination by a dermatologist revealed well-defined erythematous plaques, erythematous macules, and thick gray scales in the generalized area. Blood sugar, liver function, kidney function, and the results of routine blood tests were all within normal ranges. The histopathological analysis showed hypogranulosis, moderate spongiosis, psoriasiform hyperplasia, and dilated papillary dermal blood vessels carrying erythrocytes. This patient received five cycles of Secukinumab 150 mg subcutaneous injection therapy following the diagnosis of psoriasis Vulgaris that had been made. Each cycle of therapy resulted in a progressive clinical improvement, and by the fourth cycle, 50 days after therapy, the hyperpigmented patch lesions had diminished, and the scales were becoming thinner. In conclusion, with satisfactory results, the biological drug Secukinumab can be used as a second-line treatment for psoriasis Vulgaris, notably when methotrexate therapy has ineffective.