The invention discloses a detection method of heavy metal in soil. The detection method comprises the following steps: weighing soil, adding an alkali solution containing an ammonia solution, performing shaking and microwave treatment, adding an acid solution containing chloric acid, adjusting a pH valve, and performing ultrasonic extraction and centrifugation so as to obtain a crude extract; then performing concentration and microfiltration, and setting volumes so as to obtain a sample solution; preparing a blank solution; performing quantitative determination on the obtained sample solution by an extra-high efficient liquid chromatography. According to the detection method disclosed by the invention, an alkaline hydrolysis acid extraction method is adopted for pre-treating samples, so that losses and air pollution of heavy metal elements are avoided. Besides, the detection method has the advantages of being high in recovery rate, precision, and treatment speed, simple and convenient to operate, wide in application range and the like. According to the detection method disclosed by the invention, after the samples are pretreated, the determination of varied heavy metal elements can be performed on the pretreated samples, and performing separate sample pretreatment on each heavy metal element is not needed, so that the workload is reduced. The detection method disclosed by the invention is very acute for determining the content of the heavy metal in the soil, and has a relatively high detection efficiency.