Bijan Nikouravan Department of Physics, Islamic Azad University (IAU), Varamin-Pishva Branch, IranThe Indian Planetary Society (IPS), Mumbai, India nikouravan@gmail.comnikou@iauvaramin.ac.ir International Journal of Fundamental Physical Sciences (IJFPS) 9 4 55-58 December, 2019 2231-8186 https://doi.org/10.14331/ijfps.2019.330132 The Von Neumann entropy plays a central role in quantum information theory and is a concave function. This paper introduces a new proof for the linearity of Von Neumann entropy in the rate case without relying on traditional inequalities like Fannes'. The author shows that entropy remains linear in specific limit cases, demonstrating the relationship using spectral decomposition and density matrices. This approach reinforces the significance of Von Neumann entropy in quantum mechanics and its applications in information theory. Entropy, Von Neumann entropy, linearity https://creativecommons.org/licenses/by-nc/4.0/