By dimensionless analysis and comparison between coupled and uncoupled nonFourier thermoelastic equations and their solutions, the general non-dimensional number λ characterizing effect of thermal-mechanical coupling is given, and the effects of nonFourier thermal-mechanical coupling in materials irradiated by short laser pulse are investigated. It is shown that the thermal-mechanical coupling makes the laser-induced stress wave have higher speed, longer length and dampes swing compared with the uncoupling wave, it also excite a synchronous second temperature wave. The stress wave has saturation characteristic with increasing of parameter ε, and the stress wave can bear an exceptional dual-peak waveform under special conditions, whether it is coupling or uncoupling. The intensity of thermal-mechanical coupling depends mainly on λ, and also on the ratio of elapsed time from the pulse triggering to pulse duration, the larger the ratio value is, the stronger the coupling effect is. Therefore, large error can also be caused by ignoring thermal-mechanical coupling in analysis of a medium heated by ultra-short laser pulse, even under usual conditions with smaller absolute value of λ(10－3and lesser order of magnitude).