The invention relates to a system and a method for continuously treating soil contaminated by middle and high concentration petroleum hydrocarbon. The contaminated soil passes through a solvent extraction tower, then a solvent and an extracted petroleum hydrocarbon pollutant are connected with a solvent regeneration tower, the solvent regeneration tower separates the solvent from the petroleum hydrocarbon pollutant, and the separated solvent is connected with a solvent recovery tank; and soil and a small amount of residual solvent which come from an extraction unit are connected with a solid-solvent separation tower, the solid-solvent separation tower separates a small amount of the solvent from the soil and sends the solvent to the solvent recovery tank for recycling, the soil treated bya solid-solvent separation unit is connected with a biological remediation device, and the soil which meets the environmental standard is obtained through a biological remediation unit. The system and the method break the intermittent operation of the prior soil remediation technology and truly realize the continuous remediation of the contaminated soil. The soil remediation standard can be met through the coupling application with a microbial degradation and remediation method. The desorption efficiency is high, and the removal rate of an extracted part can reach more than 80 percent.