This research studied about pellet fuel standards around the world and the effect of particle size and moisture content on cassava pellet fuel's qualities. The sample pellet fuel from cassava root was produced in flat die pellet mill at controlling temperature 80-90 ºC. The studying parameters were particle size and moisture content. The particle size was defined by hammer mill screen sizes : 1, 4, and 10 millimeters. In the part of moisture content was defined by quantities of water addition in cassava root : 10, 20, and 30 % by raw cassava root mass. All different compound samples, cassava root pellet fuel were tested by PFI standard (The United State of America's pellet fuel standard). The qualities of pellet fuel were diameter, length, moisture content, durability, fine, heating value, and bulk density. The result from testing shown that all cassava root pellet fuel samples passed the criterion of PFI standard and other pellet fuel standards. From this result indicated that the particle size and moisture content didn't influence with all different compound cassava root pellet fuel samples.