The laser diffraction technique(LD method)has been regarded as an effective means of measuring soil particle size distribution(PSD)in recent years. To assess feasibility of applying the LD method to red soil high in clay fraction,soil samples collected from various layers of 6 forestry ferrisol profiles(clay fraction>40%)were analyzed using the LD and traditional pipette methods for comparison. It was found that the LD method is more efficient and effective and capable of providing PSD in formation of more particle size fractions,particularly of the clay fraction(<2μm),but it might "underrate" clay fraction while "overrate" silt fraction. Significant liner-relationship was found between the two methods in measured data of silt fraction and sand fraction,but not of clay fraction,because it is high in content but narrow in distribution. Modification of their models has significantly narrowed the difference between the two methods in measurement,which means the LD method can be used for PSD analysis of clayey ferrisol. However,its measurements or PSD dada are not yet ready to be used directly in the current sedimentation based triangular texture diagram to define soil texture before certain data transformation. It is an inevitable trend for LD technique to be used widely in analyzing soil PSD in the future,thus,it is urgent and significant to conduct systematical and standardized comparison studies of various typical soils,so as to improve the reliability and practicability of the LD technique,and build up a new LD-based triangular texture diagram,which will further application of the LD technique in soil science.