Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. Efficiency of the small hydroturbine is lower than that of large one, therefore there are demands for the small hydroturbine to keep high performance. Then, we adopt contra-rotating rotors, which can be expected to achieve high performance. Efficiency of the contra-rotating small hydroturbine is high in pico-hydroturbines and high efficiency can be kept in wide flow rate range. On the other hand, it is important to clarify the pressure fluctuation associated with the wake and potential interference for the stable operation of the small hydroturbine. Then, the pressure fluctuations near a trailing edge of a front rotor and a leading edge of a rear rotor are investigated by the numerical analysis. In the present paper, the pressure fluctuation of the contra-rotating small hydroturbine using different spoke geometry is shown by the numerical results.