Transparent laser ceramics are expected to be the gain medium of new high-power-solid-state lasers instead of single crystal due to their unique superior properties. Therefore, the preparation of transparent ceramics with high optical quality, high laser efficiency and high output power has become the hot point of current research. However, sintered polycrystalline ceramics have a certain amount of grain boundaries and pore defects. The relationship between the porosity and the performance of ceramic lasers and the latest research progress in controlling the porosity of ceramic materials are interviewed. Studies have found that the porosity has a greater impact on the scattering coefficient, transmittance, laser threshold, and laser slope efficiency of laser ceramics. Controlling the ceramic preparation process and optimizing the preparation process can reduce the porosity of the laser ceramic material, thereby improving the optical performance of the laser ceramic material.