The High-speed trains are powered by sliding electrical contact between pantograph and catenary. During train operation, catenary resonance will increase the amplitude of pantograph and catenary, resulting in a larger range of fluctuation of the pantograph-catenary contact force, increasing the offline rate of the pantograph-catenary, decreasing the quality of the pantograph-catenary receiving current, and affecting the safe and stable operation of the train. In order to avoid the generation of pantograph-catenary resonance and ensure the safe and stable operation of high-speed trains, it is urgent to study the frequency response characteristics and modal vibration patterns of pantographs. In this paper, the frequency response characteristics of pantographs are investigated by modal analysis. The modal vibration patterns of the pantograph in the vertical, transverse and longitudinal directions are obtained through tests, and the frequency response characteristics and modal vibration patterns of the pantograph in the three directions below 50 Hz are analyzed. The test results show that, among the frequency response characteristics of the pantograph in three directions below 50 Hz, there are 8 orders of intrinsic frequency in the vertical direction, which are 4.0134 Hz, 6.0129 Hz, 8.8904 Hz, 11.4671 Hz, 24.4855 Hz, 30.9296 Hz, 32.8563 Hz, and 35.7977 Hz, respectively; there are 4 orders of intrinsic frequency in the horizontal direction, which are 10.4565 Hz, 21.4058 Hz, 26.86 Hz, 35.6036 Hz; and longitudinal direction has 8 orders of intrinsic frequency, which are 6.9861 Hz, 8.1597 Hz, 10.5063 Hz, 12.5245 Hz, 26.8091 Hz, 31.1811 Hz, 35.9983 Hz, and 40.6962 Hz.