The invention discloses a measurement system for a building material surface convective heat exchange coefficient. The measurement system consists of a thermal insulation box, industrial fan, an anemometer, a small automatic weather station, thermocouple temperature sensors, an air temperature sensor, a water temperature sensor and a building material test piece. Thermal insulation box and the building material test piece compose an enclosed box; the water temperature sensor is disposed in the thermal insulation box; the thermocouple temperature sensors are disposed on the surface of the building material test piece; the air temperature sensor is arranged in an external environment; and the thermocouple temperature sensors, the air temperature sensor, the water temperature sensor and the anemometer are all connected to the small automatic weather station for real-time acquisition and storage of test data. Based on the theory of heat transfer, the measurement system and method providedby the invention can achieve efficient, simple and accurate measurement of the convective heat exchange coefficient between a building material and the external environment, also take the heat absorption and heat release processes into account, can better simulate the thermal behavior of an actual engineering structural material in a service environment, and have good application prospects.