The invention discloses a method of refining and desulfurizing for low-silicon steel. The method includes the steps of adjustment of a slag system, slagging, heating and desulfurizing; the to-be-refined low-silicon steel comprises the components of less than or equal to 0.03% of Si and 0.020-0.030% of S. Aluminum powder is added in a steel ladle to regulate the slag system to reduce oxidability ofslag firstly, and then lime and fluorite are added to perform slagging. Calcium carbides are added when liquid steel is heated to a temperature of more than 1600 DEG C, the weak reducibility of the calcium carbides are used for removing oxygen of the refined slag to further accelerate desulfurization, and achieving the purpose of reducing sulphur content in the liquid steel. The reducibility of the calcium carbides is weak and cannot restore silicon in the slag, so that the increasing of the silicon content in the liquid steel can be avoided, oxidative product of the calcium carbides is carbon monoxide, and the submerged arc effect in the refining process can be improved.