The invention provides a method for separating tin from a waste tinned copper cable. The method comprises the steps that first the waste tinned copper cable and inorganic salt powder with the mass ratio of the waste tinned copper cable to the inorganic salt powder being 4:1 are added into a reactor, the interior of the reactor is kept as a vacuum system, heating is conducted to make the internal temperature of the reactor be 165-200 DEG C, and continuous stirring treatment is conducted for 20-30 min; meanwhile, the internal temperature of the reactor is increased to be 320-350 DEG C, heat is preserved for 20-30 min, residual tin on the surface layer of the waste tinned copper cable, scraped tin particles and the inorganic salt powder are all melted into a liquid state, and liquid tin and inorganic salt enter a collecting hopper through a screen net below the reactor; and heating and stirring are stopped, cooling is conducted, and a detinned copper cable, a tin bar and an inorganic saltsolid body are obtained. According to the method for separating the tin from the waste tinned copper cable, the technology is simple and efficient, the device is safe and reliable, operation is convenient, the separating and recovery effects are good, and further industrialized scale-up production can be achieved.