The characteristic of the polarization curve and the parameter variations of open circuit voltage V-0. Tafel slope b and ohmic resistance R in the curve are experimentally investigated through a 150 h strengthened vibration test in this paper, to analyse the steady-state performance of the fuel cell stack under long-term vibrating conditions on strengthened roads. The load spectra applied in the test are simulated by the acceleration signals of the fuel cell stack, which are previously measured in a vehicle vibration test. The load signals of the vehicle vibration test are iterated through a road simulator from vehicle acceleration signals which are originally sampled in the strengthened road of the ground prove. During the test, the current and voltage under steady-state operation of the stack were measured six times at regular intervals. The test results indicate a fluctuating variation of the polarization curves. In the meantime, the V-0 decreases by 3% of the original value, R increases by 55.8% and b declines by 28.0%. From the results it can be concluded that the strengthened road vibration exert a significant influence on the steady-state performance of the fuel cell stack, which cannot and should not be ignored during the research. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.