Abstract: OBJECTIVE To study the microscopic film-forming process of film coating, and realize the construction of non-destructive testing model for coating quality. METHODS The microcrystalline cellulose tablets were coated with polyvinylpyrrolidone as a coating shell material, and rhodamine was added as a tracer in the coating shell material. The coating weight gain and film thickness of coated tablets were measured at different coating times, and the microstructure and macroscopic profiles of the coated film were determined by confocal laser scanning microscopy and near infrared spectroscopy, respectively. Then chemometrics method was utilized to correlate the near infrared spectra with the film quality, and finally the control models for the coating process was constructed. RESULTS The film was inhomogeneously distributed on the surface of the tablets. It was primarily disturbed on both sides of the tablet and subsequently distributed on the curved portions. This difference gradually decreased with the progress of the coating. In addition, the microstructure indicated that there exists microporous structure on the surface of the film. Near infrared spectra after multiple scattering correction pretreatment could accurately control and predict the coating quality. CONCLUSION Confocal laser scanning microscopy and near infrared spectroscopy can enhance the understanding and control of film coating from microscopic and macroscopic aspects, and help to develop and utilize the film coating technology.