The invention discloses an automatic separation type isolation guardrail in the middle of a road. The automatic separation type isolation guardrail in the middle of the road is characterized in that the automatic separation type isolation guardrail is formed by connecting a plurality of guardrail units; each guardrail unit comprises special-shaped bases, stand columns and a guardrail basic unit, the stand columns are arranged on the two sides of the guardrail basic unit, and the bottom ends of the stand columns are inserted into the special-shaped bases; the top ends of the adjacent stand columns of the adjacent guardrail units are connected in a weak shearing mode through wedged connecting pieces, the interiors of the adjacent special-shaped bases for placement of the adjacent stand columns are connected through torsion devices, and the torsion devices are rotated and separated after being stressed. With the automatic separation type isolation guardrail, not only can opposite-direction traffic flows be separated, but also the safety of the isolation guardrail can be improved; damage to vehicles on opposite-direction traffic lanes generated by overall toppling of the isolation guardrail caused by overlarge collision force between the vehicles is avoided, the influences on the opposite-direction lane capacity are relieved, the safety of drivers and the vehicles is improved, and the effect of non-toppling in slight collision and separation in severe collision is achieved.