The invention provides an N-benzyl-N-arylsulfonamide derivative, which is an N-benzyl-N-arylsulfonamide compound represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof. The N-benzyl-N-arylsulfonamide derivative is obtained by condensing a substituted nitrobenzene with 5- or 6-membered nitrogen-containing aliphatic heterocycle (the ring B), reducing the nitro group to an amino group, and subjecting the amino group to reductive amination, sulfonamidation; or by subjecting a substituted nitrobenzene to nitro reduction, reductive amination and sulfonamidation, and condensing the resultant intermediate with 5- or 6-membered nitrogen-containing aliphatic heterocycle (the ring B). It has been experimentally demonstrated that the N-benzyl-N-arylsulfonamide derivative of the invention can specifically bind to Kv1.3 potassium channel and inhibit or decrease its activity, and is useful in the treatment of autoimmune diseases caused by abnormal activation of the Kv1.3 potassium channel in human or animals. The invention further provides a medicament or a pharmaceutical composition comprising the N-benzyl-N-arylsulfonamide derivative.