Abstract: This paper reported that incinerating temperature effects on assaying content of Cu、Mn、Fe and Zn microelements when porcelain crucible incinerated Brassia oleracea leaves and Mongolian oak leaves were used as samples. The results indicated that the method was feasible in using porcelain crucible for incinerating of plant samples under high temperature. When assaying contents of Cu、Mn、Fe and Zn microelement. The optimum incinerating temperatures were 450～550、 450～550 、450～600、450～500℃, respectively the optimum incinerating temperature would be 450～500℃ when assaying the contents of this four microelement at the same time. The recovery rate of microelement was 96%～108% when incinerating temperature was 500℃.

Key words: porcelain crucible, incinerating temperature, plant sample microelement