The invention discloses a method for preparing all-purpose soil from soil contaminated by petroleum hydrocarbons. The method includes the following steps: drying and pulverizing the soil contaminatedby the petroleum hydrocarbons, performing oxygen-limited pyrolysis at 200-400 DEG C for 1-5 hours, and cooling down to room temperature to obtain a biochar-like soil pyrolysis product having a large amount of carbonaceous materials on the surface; mixing the biochar-like soil pyrolysis product with turf, humic acid, vermiculite, organic wet garbage compost, perlite, bentonite, medical stone and complex microbial inoculants, and performing sufficient stirring to obtain the all-purpose soil. The method has the advantages that local materials are utilized by the low-temperature oxygen-limited pyrolysis technology, so that toxic and harmful substances in the soil contaminated by the petroleum hydrocarbons are removed, and most of soil organic carbon and nutrients are maintained; the soil is wrapped by a carbonaceous material to enhance the soil fertility; the defects of traditional remediation techniques for the soil contaminated by the petroleum hydrocarbons, such as large investment, high time consumption and slow action, are overcome; the method has the advantages of simple and easy process, good effect, low cost and the like.