We analyze a class of SIV system considering effective vaccine protection and protective measures, in which the effective vaccine protection rate is represented by a piecewise-smooth function. This piecewise function is composed of three segments. When the number of infected people exceeds a set threshold, the effective vaccine protection rate is increased based on the first paragraph. To further increase the effective vaccine protection rate to 1, we should take into account not only the influence of the number of infected people, but also the diagonal dividing line of the interaction between the number of infected people and that of vaccinated people. We analyze the global dynamical behavior of the SIV system using the discontinuous differential equation theory, Filippov convex method and other methods, and the theoretical results could provide recommendations for vaccination. Then, in order to achieve the best vaccine protection effect, we analyze the selection of the threshold and the two values of the vaccination effective protection rate using numerical simulation.