The invention discloses a shaft crack simulator, which comprises a shaft and a crack simulating pipe, wherein the shaft is connected with the crack simulating pipe; an inner pipe is arranged in the center of the shaft; the upper part of the outer wall of the shaft is provided with a pressure gauge, a restrained pressure pipeline joint and a slurry return port; the lower part of the outer wall of the shaft is provided with a connecting interface used for connecting the crack simulating pipe; a pressure sensor joint is arranged on the outer wall of the shaft; the crack simulating pipe is connected with the connecting interface of the shaft through a tail flange; a concrete column is arranged in the crack simulating pipe, a passage is formed in the middle of the concrete column; a cement crack pouring short section is arranged at the top end of the crack simulating pipe; a simulated crack is formed in the center of the cement crack pouring short section; and the simulated crack is communicated with the passage in the middle of the concrete column. The shaft crack simulator can simulate the process of leakage loss treatment during well drilling, and test the plugging capacity of a plugging material to crack type leakage losses.