A condensing system is used to generate a condensing layer on a surface of a test object. The condensing system includes airflow generating device and a passage device. The airflow generating device is used to generate condensing airflow. The condensing airflow has a dew point higher than a temperature of the surface of the test object. The passage device is connected to the airflow generating device, and the condensing airflow flows from the airflow generating device into the passage device. The passage device includes a flow-uniforming module. The flow-uniforming module includes at least one uniforming board. Each of the at least one uniforming board has at least a first hole.