Measurement of wheel/rail contact forces is of importance. Traditional methods for wheel/rail interaction force measurement all need strain gauges on wheel sets and/or rails. Because strain gauges have the performances of zero-drift, poor anti-interference property and instability of test system, they can’t meet wheel/rail force test requirements in high-speed and heavy haul railways. A new method based on PVDF piezoelectric sensing technology is presented for the test of vertical and horizontal wheel/rail force in this paper. Firstly, based on the wheel/rail interaction characteristics, the restriction condition of track and strain sensing principle of PVDF films, principle for measuring vertical and lateral wheel/rail interaction forces is proposed. Then a series of tests were carried out to compare the performance of PVDF strain sensors with the one of strain gauges. The results show that the PVDF strain sensor has better reliability in wheel/rail force monitoring. Finally numerical analysis by Finite Element Method has been carried out to verify the feasibility of the method presented in this paper.