The invention discloses an extraction separation system for separating rubidium ions from salt lake brine. The extraction separation system involves an extraction agent and a diluting agent, wherein the molar concentration of the extraction agent in the diluting agent is 0.05-2.50 mol/L, the extraction agent is at least one of 18-crown-6 and derivatives thereof and 21-crown-7 and derivatives thereof, and the diluting agent is a hydrophobic ionic liquid. The system can effectively solve the problem that an existing separation system uses an organic solvent as a diluting agent, the organic solvent is prone to volatilize, so that the environment is influenced seriously; and meanwhile, the extraction effect of the rubidium ions can be improved.