A tire rolling resistance testing machine has: a main testing set, an X-axis sensing member and a Y-axis sensing member. The X-axis sensing member and the Y-axis sensing member are configured for testing the tire, wherein the first connecting member and the second connecting member are floatingly mounted between the two X-axis positioning plates and the two Y-axis positioning plates which allow the axial rod to be placed through and perform the test. This design greatly improves the sensitivity of the first connecting member and the second connecting member, and avoids the mutual interference between the X-axis moment and the Y-axis moment when the tire is tested. Therefore, the precision of the test and the accuracy of rolling resistance data is improved.