The utility model relates to a detection device, in particular to a probe used for measuring the corrosion rate of metal material in atmospheric environment. The probe comprises an excitation signal input terminal (1), a test piece tray (2), a plurality of corrosion coupons, a temperature compensation test piece (5), an excitation signal output terminal (6) and a plurality of response signal measuring terminals. When detection is performed, an interface of the probe is connected with a detection circuit, and same DC excitation signals are applied to the corrosion coupons and the compensation test piece; excitation response signals at two ends of the corrosion coupons and the compensation test piece are obtained, the amount of thickness reduction of the corrosion coupons is calculated, and the corrosion rate of the metal is derived according to the thickness reduction amount. The probe provided by the utility model has the advantages of small error of measurement, high sensitivity, strong anti-interference capability, and wide application scope, and can realize remote on-line measurement.