Because the pressure propagation in earth completes instantly, the water flooding response is re-defined as the time when the ratio of the result of flood development deliverability minus resilience development deliverability and resilience development deliverability reaches one percent. With the modified definition, the single phase flow's water flooding response and its affecting factors in a five-spot water flooding pattern are studied by numerical simulations when the production well is an infinite conductivity vertical fracture well and the injection well is a straight well. Permeability greatly affects the water flooding response, and water flooding response sharply increases with decrease of permeability, especially when the permeability is smaller than 10 md. The bigger the well spacing, the longer the water flooding response, and the increase of water flooding response is getting faster with spacing's increase. The higher the injection volume, the shorter the water flooding response, and the decrease of water flooding response is getting smaller with injection volume's increase. Measures can be taken such as injection ahead of time, with smaller well spacing and higher injection volume when permeability is too small.