Abstract: The rock elastic resistance coefficient K is an important parameter and reflects the resistance of the rock around the tunnel in hydraulic tunnel engineering. It is found that the elastic resistance coefficient calculated by tunnel excavation supporting is entirely consistent with the coefficient calculated by hydrostatic test. The finding is based on the comparative analysis of mechanical effect relations under elastic state between tunnel excavation supporting and hydrostatic test. Back analysis method of elastic resistant coefficient from the measured displacements of the tunnels is proposed. According to the construction of shallow buried hydraulic tunnel in loose ground, a comprehensive monitoring on the displacements of the tunnel is performed during construction. Based on the measured data and the proposed inversion method of elastic resistant coefficient, the elastic resistant coefficient is obtained. The method, analysis and conclusion of research can be valuable experience and reference for design, construction, supervision and further theoretical research on tunnel engineering under similar conditions.