In order to examine the toughness of concrete circular plates reinforced with a new type of macro polyolefin fiber, a circular plate test was performed and the effects of fiber use level, fiber length and the matrix strength on the flexural toughness, energy absorption value were investigated. The test results show that the absorption energy value is proportional to fiber use level; when fiber length is between 38 to 60mm, the absorption energy value increases with increasing fiber length. When the fiber length is greater than or equal to 48mm, in the descending stages on the load deflection curve strain hardening behavior appears with two peak loads. The problems with evaluating the flexural toughness using ASTM C1550 were analyzed based on the energy ratio method, and a new toughness evaluating method was proposed. This new method, taking the first crack deflection as the initial reference deflection, can be used to characterize the contribution of macro polyolefin fiber to the flexural toughness after initial crack, and can directly used to compare the toughness index with perfect elastoplastic material.