Highway pavement flatness detection device and detection method thereof

The invention relates to the technical field of highway pavement flatness detection, in particular to a highway pavement flatness detection device which comprises a machine base, a supporting table, a plurality of moving wheels and a control box, and further comprises a plurality of wheel seats movably arranged on the machine base at equal intervals and elastically connected with the machine base; one end of each wheel seat is movably provided with one detection wheel; the spray head is arranged on the wheel seat, is positioned on one side of the detection wheel and is communicated with the wheel seat; the number of the detection execution modules is the same as that of the wheel seats, the detection execution modules are arranged on the machine base and connected with the wheel seats, and the detection execution modules are connected with the valve structures; the driving module is arranged on the machine base and is connected with one moving wheel; the monitoring module is arranged to monitor the slope of t