The work aims to evaluate whether the film is competent on a specific substrate surface under a known load by directly measuring the critical strain of thin films. The in-situ three-point bending test method under the micron scale was proposed by scanning electron microscope (SEM)/focused ion beam (FIB) analysis and test system. At the same time, the real-time observation, analysis and record were carried out. Then, magnetron sputtered technology was used to prepare highly preferentially oriented CrN film, and Cr/CrN multilayer film and the above in-situ three-point bending test method was utilized to conduct bending test on the two films The measured results showed that, the critical strain of the thin CrN film was (1.8±0.1)%, with its deformation type before failure being elastic rather than plastic or mixed. Remarkably, the critical strain of multilayer Cr/CrN film reached as high as 9.1%, 5 times that of CrN film. Moreover, the Cr/CrN multilayer film was insensitive to preliminary cracks. By combing the residual stress measurements at the micron scale using FIB, the in-situ test method can be used to evaluate the deformation capability of various thin films and to provide a guidance for the design of tribological films for specific applications. The obtained performance data of thin films have a good guiding significance for the selection and design of thin film systems or structures for different substrates and different working conditions (such as different surface stress states and deformation states, etc.).