The invention provides a test device and a test method for measuring the free expansion volume of a high polymer. The test device for measuring the free expansion volume of the high polymer comprisesa test chamber and a measurement chamber, and the test chamber and the measurement chamber are communicated. The test chamber is provided with a temperature measurement device. The test chamber is further provided with a grouting head and an exhaust valve. A partition plate which divides the measurement chamber into a measurement chamber A and a measurement chamber B is arranged in the measurementchamber. Only the lower ends of the measurement chamber A and the measurement chamber B are communicated, and the measurement chamber A and the measurement chamber B form a communicating vessel. Themeasurement chamber A is communicated with the test chamber A. The measurement chamber B is communicated with the test chamber through the measurement chamber A. Observation windows are arranged on the measurement chamber A and the measurement chamber B respectively. Scales are arranged on the observation windows. The upper end of measurement chamber B is open or provided with a valve communicatedwith the outside. A more complete device is provided for the study of the free expansion characteristic of the high polymer. The acquired test result can provide a basis for the study of the groutingrepair of an infrastructure safety protection high polymer.