Abstract: Based on the elastodynamic analysis method, the sound radiation performances are studied for planar elastic linkage mechanisms. Firstly, the surface normal displacement and velocity vectors of the links are derived. Secondly, the sound radiation performances such as sound pressure levels and sound power levels are calculated. Finally, numerical simulations are carried out on a 4-bar linkage mechanism. The simulation results show that the sound power level is varied with the speeds and positions of the crank, the lower order resonance phenomena for sound radiation also exists at certain running speeds.