A device measuring bonding strength of soft coating based on laser thermal effect was established, and the mechanism and method for characterizing interfacial bonding strength of coating by residual stress under laser action were analyzed, which is suited for measuring bonding strength of soft coating. The experimental results show that residual stresses of the coating are changed under laser thermal stress, and residual stress in the node can be used to measure the interfacial bonding strength of the coating. Tradition pulling method can be replaced by the method of coating interfacial bonding strength with laser thermal stress, and the real time measurement of coating bonding strength was realized in the real-time way.