Mechanoluminescent materials have gained considerable attention over the past few years due to their unique characteristic of converting some useless mechanical actions in our daily life like compression and friction into usable light sources. However, the application scenarios of mechanoluminescent materials are still quite limited, mainly to stress sensors and visualization of pressure. Our work aims to solve this problem, and to show how to extend the mechanoluminescent materials for optical thermometry theoretically and experimentally. Here we demonstrate that Y2O2S:Er3+ with excellent mechanoluminescence (ML) could be used for energy-saving temperature sensing. Upon stimulation of external force, Y2O2S:Er3+ emits bright green ML that is attributed to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+. These transitions are confirmed to conform with the Boltzmann distribution during dynamic temperature-changing test. In addition, we confirm the feasibility of ML thermometry framework in Er3+-doped Gd2O2S and Lu2O2S. Our work provides a new perspective for broadening the application scenarios of mechanoluminescent materials.