The target porosity was prefabricated by adding different content of expanded polystyrene (EPS) particles to simulate different hole defects of concrete, and concrete specimens with different porosity levels of C25 and C30 were prepared to develop the mechanical properties of concrete with hole defects under monotonic and reciprocating loading. In the experimental study, the changes in the shape, strength, strain and elastic modulus of concrete specimens with porosity were analyzed, and the influences of different hole defects on the static and dynamic properties of concrete were discussed. The test results show that under monotonic and reciprocating loading, the concrete specimens without prefabricated hole defects show brittle failure characteristics. However, with the increase of porosity, the strength of concrete specimens decreases significantly, and the stress-strain curve gradually tends to distribute in a fish-maw shape. The specimens change from brittle to ductile failure and gradually show the characteristics of multi-crack propagation, especially for reciprocating loading. Under the two loading methods and two strength levels, the main mechanical properties of the specimens show consistent changes with the increase of the precast porosity. Peak stress and elastic modulus decrease exponentially with the increase of porosity, while peak strain and extreme strain increase linearly. The influence of porosity on the mechanical properties of specimens under reciprocating loading is greater than that of monotonic loading, and this effect decreases with the increase of concrete strength. In the reciprocating loading process, the greater the porosity, the greater the stiffness ratio of the specimen before the peak stress, and the more serious the stiffness degradation after the peak. For the same porosity, the higher the concrete strength grade, the smaller the stiffness growth rate before the peak stress and the less the degree of stiffness degradation after the peak.