Abstract: Objective:To explore the differences of five kinds of trace elements between edible cooking oil and hogwash oil.Methods:Different kinds of 5 parts edible oil and 1 part homemade lard oil,3 parts old cooking oil and 3 parts hogwash oil were collected.In each sample,0.3 ~ 0.4 g was weighed accurately.The samples were digested into a solution for determination by microwave.The contents of copper(Cu),zinc(Zn),manganese(Mn),lead(Pb) and iron(Fe) were determined by atomic absorption spectrometry.Results:In the experimental concentration range,the recovery rate was between 97.6% to 102.4%,the relative average deviation was 0.6% to 2.5%.The contents of 5 kinds of trace elements in old cooking oil were similar to soybean oil,and there had no differences of Cu,Zn,Mn and Pb contents between the edible oil and hogwash oil,whereas Fe content in old cooking oil and hogwash oil was higher than that in the edible oil(P<0.01).Conclusions:There had no statistical differences of elements Cu,Zn,Mn and Pb contents between the edible oil and hogwash oil.Fe content was increased in hogwash oil,which may be due to the long-term exposure to the iron products when the hogwash oil was refined and transported.