The addition of fiber into concrete can not only suppress the interior shrinkage strain and decrease the thermal dilation coefficient (TDC) of concrete, but also it can lessen the width of shrinkage crack, especially reduce the appearance of interconnected pore, thus the reduction of the water content of capillary pore will make the TDC of paste matrix lessen. In this paper, an experiment was designed to study the TDC from the 5th day to the 29th day after the concrete was poured. The results show that the addition of fiber can effectively reduce the TDC of concrete. When the addition is the same, high-modulus carbon fiber reinforced concrete has a lower TDC than low-modulus polyester fiber concrete.