Abstract: In order to improve the accuracy of heavy metal analysis in soil, the author compares and analyzes the contents of chromium, copper, nickel, zinc and lead by discussing the influence of sample weight, acid-removing temperature, adding perchloric acid, and standard addition method in the digestion process. The results show that the recommended sample size of soil or sediment samples is 0.200 0-0.250 0 g, the optimum temperature for acid removal is 140℃, and perchloric acid may be added or not; for the soil or sediment samples which are difficult to digest, the sample size is recommended to be 0.100 0 g. Perchloric acid can be added after digestion to improve the dissolution rate of elements; when the acid-removing temperature is 170℃, the element loss is the least and the time is moderate; except for lead, the standard addition method of the other four elements has no obvious difference from the common curve.