This paper deals with the matrix absorption and enhancement effects of thick targets in energy dispersive X-ray fluorescence analysis. Two kinds of absorption correction methods are studied especially for medium thick targets (5-10 mg/cm²). For analysis of hair samples, both the measurement of absorption correction coefficients and the determination of sensitivity factors using an addition method are introduced. Quantitative analysis of medial thick samples is established. The relative deviation between different methods for most of the elements is found to be less than 5 %.