Abstract：With the increase of electric locomotive’s speed, the offline which caused electromagnetic interference of catenary and pantograph has become an important factor restricting the development of high-speed railway. In order to study the theory of electromagnetic compatibility in the pantograph-catenary system, an electromagnetic noise experimental system was developed. The device consists of the electric wave darkroom, the device of pantograph-catenary arc and the arc detection system, which can acquire the contact voltage and contact current collection, contact temperature and contact pressure. Different contact force, contact current and sliding speed conditions, 64 groups of electromagnetic noise experiments were conducted. It uses the FFT to analyze the DC component. Experimental results show that when the sliding velocity and contact current is constant with the increase of pressure, the rate of current interruption is decreasing in current signal, and the DC component is going up. When the contact current and contact pressure is constant with the increase of sliding velocity, the rate of current interruption is increasing in current signal, and the DC component is going down.