The utility model discloses a distillation system for ethylene glycol and diethylene glycol in polyol waste liquid. The device comprises first and second rectifying towers and a vacuumizing device, wherein the first rectifying tower comprises a first tower body, a first reboiler, a first condenser, a first separator and a first pump; the second rectifying tower comprises a second tower body, a second reboiler, a second condenser, a second separator and a second pump; the structure is simple and the operation is convenient; the reflux ratio of ethylene glycol to diethylene glycol is controlledby arranging two valves; the purpose of separating high-purity ethylene glycol and diethylene glycol is achieved, the purity of ethylene glycol and diethylene glycol can reach 99.7% or above, the recycling standard of enterprises is met, the recycling cost of ethylene glycol and diethylene glycol is effectively reduced, in addition, the load of environment-friendly equipment can be effectively reduced, and the environment-friendly expenditure of enterprises is reduced.