Abstract: Though tunnel entry waves belong to the category of infrasound and are usually weaker than micro-pressure waves, they could cause a new environmental problem with further speed up of future high-speed trains. In the present study, numerical investigation of the tunnel entry waves induced by a high-speed train CRH380A running into a typical China tunnel is performed using a CFD code STAR-CD and adopting arbitrary sliding interface(ASI) method, which is based on the finite volume method(FVM). To solve the governing equations of three dimensional, compressible and unsteady turbulent air flow around the high-speed train, the PISO algorism and Shear-Stress Transport (SST) k-ω turbulence model are used. The high-speed train is allowed to accelerate gradually from stationary to a constant speed in order to avoid unphysical pressure fluctuation in air flow during numerical iteration. The validity of the present numerical method is carried out through a preliminary study on a revolutionary ellipsoid train model, of which the experimental and numerical results are accessible from literatures of Japan scholars. Thereafter, taking high-speed train CRH380A as an example, based on analysis of variation performance of a moving quasi-steady pressure field, i. e. passing-train pressure field, the basic characteristics of tunnel entry waves are revealed. It is also showed that the tunnel entry wave has directivity towards the forward direction of the train. Study on the train speed dependency shows that the magnitude of entry waves is proximately proportional to the cube of the train speed, implying that the higher the train speed, the more noticeable the tunnel entry waves and its influence. Furthermore, the spectral analysis shows that the main frequency of tunnel entry waves is less than 7 Hz, and the magnitude and SPL of it are decrease along its propagation. However, the influence of tunnel entry waves induced by CRH380A on surroundings is rather weak because of its slender nose and tail shape.