Abstract: Nature-like fishways not only satisfies the migration needs of different fishes, but also increases the diversity of fish habitats in river channels. It is the hot research area, to which researchers pay much attention recently. For the complexity of the structure, the variability of cross section type, and the difficulty of roughness calculation at bottom and side slope, there is no accepted and perfected method to study the flow condition of nature-like fishways at present. This paper takes nature-like fishway of Xin'gan hydro-junction as research object. An integral physical model test with scale of 1:12 is established to explore the feasibility of flow conditions in fishway scheme. The results show that the research methods of technical fishways can be used to control the parameters of nature-like fishways such as bottom slope, bottom width, pool length, deviation rate, permeability, and so on. Then the integral physical model test with validation and optimization can be applied to guide the design of nature-like fishways. Compared to technical fishways, the velocity difference in nature-like fishways route is obviously influenced by size error of cross section and construction material. Especially, in the curved section of fishways, the deviation rate is affected by the curve, and the velocity is easy to be higher or lower than the one in the straight route. The research may offer a sound basis for engineering design, and also provide a frame of reference to study the nature-like fishways.