The aim of the research was studied some engineering properties of Arabian coffee seeds (Himy, Esmaely and Ma'arepy) varieties to analyze the behavior of the product to design threshing and grading machines. Three categories of the coffee grains were used to measure the main dimensions (length, width, thickness), mass, density, porosity, angle of repose and coefficient of friction. The overall means of volume, geometric diameter, arithmetic diameter, cross-section area and spherisity were determined. The highest frequency length, width and thickness of the coffee been seeds were 10, 7 and 7 mm, respectively. The medium categorize (from 7 - 10 mm) was denser than both small and large sizes of coffee bean as the porosity of that size was lower than those of both small and large sizes. The angle of repose increased with the decrease of coffee bean sizes as the relation with coffee bean seeds spherisity. The coefficient of friction decreased with the increase of coffee bean size at all surfaces. The maximum coefficient of friction was occurred on plywood surface followed by galvanized steel, tin plate, and glass for all categories of the coffee bean seeds.