There are two transmission routes for cholera: the direct (human-to-human) and indirect (human-to-environment) transmission. Considering these two transmission mechanisms, a partially degenerate reaction-diffusion equation model is constructed to study the effects of seasonality and human activity on the spreading of cholera. First, we obtain the existence, un-iqueness and non-negativity of the solution and prove that the solution is ultimately uniformly bounded. Second, the basic reproduction number is identified, and it is shown that the disease will extinct when the basic reproduction number is less than 1. When the basic reproduction number is greater than 1, the global attractivity of the unique positive periodic solution is established using monotonic iteration method, which indicates that the disease will persist. Finally, we numerically explore the influences of key model parameters on the basic reproduction number. The results show that the spatial heterogeneity may reduce the risk of disease transmission, while the seasonal factors do not always contribute to the spread of cholera.