In high-speed conditions, when moving loads reached certain speed, the structure would vibrate heavily. In this paper according to the vibration differential equation of Winkler beam under moving loads, critical speed expression was obtained. Then the influences of foundation supporting stiffness and moving loads speed to Winkler foundation beam vibration were studied in detail. The conclusions are as follows: (1) Critical speed and dynamic deflection of Winkler foundation beam grow with an increase of moving loads number. Moving loads superposition lead to critical speed increase and vibration intensified. (2) When foundation supporting stiffness decrease, the whole vibration area of Winkler foundation beam moves to the lower speed regions and vibration strength increases rapidly. (3) It is also proved that the increase of Winkler foundation supporting stiffness can effectively improve the critical speed of Winkler foundation beam.