A high-purity n-tetrasilane purification method includes: introducing a tetrasilane (Si4H10) isomeric mixture into a solidifying purification tank, cooling the tetrasilane (Si4H10) to a predetermined temperature with refrigerant in the solidifying purification tank, maintaining the predetermined temperature between the freezing temperature of the n-tetrasilane (n-Si4H10) and of the i-tetrasilane (i-Si4H10), solidifying the n-tetrasilane (n-Si4H10) in the tetrasilane (Si4H10) isomeric mixture into solid state, and vacuuming the i-tetrasilane (i-Si4H10) from the mixture for separation.