A device and a method for detecting the road surface compaction effect are provided. The device comprises a fiber bragg grating demodulator, a pressure sensor for detecting the pressure of a road surface, and a displacement sensor for detecting the thickness of the road surface, wherein the pressure sensor, the displacement sensor and the fiber bragg grating demodulator are connected. According to the invention, the principle is simple, the operation is convenient, the detection is accurate and rapid, and objective and efficient detection is implemented. The reliability and the detecting reliability are good, the manufacturing cost is low, the energy consumption is low, the scope of application is wide, the practical value is high, and the detecting device is convenient to use and maintain. The detecting method is simple and convenient, the detecting process is simple, the detecting time is short, the detecting is not affected by the outside environment, the road surface compaction effect can be rapidly and accurately detected to provide a reliable basis for the reasonable detection and construction, and the defects that the consumed time is long, the operation process is complex and the detection is largely affected by the outside environment during the detection of the road surface through a drilled core method in the prior art are overcome.