The effect of temperature change on dynamic performances of planar 3-RRR flexible parallel robots is studied in this paper. In general, the strain and stress are produced not only by the external exciting force, but also by temperature change. The strain energy that is caused by temperature change should not be ignored. Based on the Hamilton principle and the finite element method, the general equations of motion of 3-RRR systems are determined, in which the effect of temperature change is taken into consideration. The equations of motion of planar 3-RRR flexible parallel robots are solved using Gear’s algorithm. The commercial Ansys 13.0 software is used to confirm the validity of the theory model. The effect of the daily temperature change of different cities on the performance of 3-RRR flexible parallel robots is investigated. Numerical results show that a small temperature change will cause a significant change in the stress of the flexile links of planar 3-RRR flexible parallel robots. The effects of temperature change should not be ignored when analyzing the dynamic performances of planar 3-RRR flexible parallel robots.