A well cementation cement sheath integrity simulation and evaluation tester includes pressing joints, wherein the pressing joints are arranged on compress packings; screwing compression rings are connected with compress discs through screw threads, and fix trapezoid rubber seal rings onto the compress discs and a steel tube; the steel tube containing a well cementation cement solidified body test sample is clamped tightly by screw rod and screw nut connecting assemblies and connected with the screw rod and screw nut connecting assemblies into a whole; pressing blocks and a mechanical pressure device are connected together to exert mechanical extrusion force to simulate the process that underground pressure variation causes damage and micro cracks to an oil well cement sheath; the pressing joints and a fluid pressing device are connected, so as to exert fluid pressure, simulate fluid pressure of the formation fluid on the well cementation cement sheath, and test and evaluate anti-channeling strength of the well cementation cement sheath; cured samples are placed in the well cementation cement sheath mechanical property simulation tester for test and analysis; and the tester can detect variation situations of the anti-channeling strength of the well cementation cement sheath under different conditions, so that impacting ductility and packing reliability of the well cementation cement sheath can be evaluated accurately.