Based on the standard of ASTM C1550, test of circular plate was for the first time introduced in China to examine the effect of a new kind of macro polyolefin fiber on the flexural toughness of fiber reinforced concrete plate. Compared with the flexural toughness test of beams, it is shown that the test of circular plates is more suitable to evaluate the flexural toughness of macro synthetic fiber reinforced concrete. The energy absorbtion value increases with increase in fiber length and volume. Applying the evaluation system of Japan JSCE SF4, for the same fiber quantity 6, 8, 11kg/m3, the flexural toughness index of polyolefin fiber reinforced concrete was increased by 101%, 68%, 76% higher than that of mid elastic modular fiber respectively and 65%, 90%, 138% higher than that of 156kg/m3 steel fiber.