In order to obtain the true mechanical response of UHPC（ultra-high performance concrete） pavement of steel bridge deck, a field loading test was carried out on Tongji Road steel bridge in Shanghai. The strain response characteristics of pavement under static load, dynamic load and in operation period were analyzed. Results show that the maximum tensile strain area of the pavement layer is on the top of the pavement layer which is above the U-shaped rib side, and 0.25 m from the diaphragm plate longitudinally. The direction of the maximum tensile strain, with a value of 25.1×10^-6, is transverse. The dynamic response characteristics of UHPC pavement under dynamic load are different from those of steel bridge asphalt pavement. The tensile strain value of UHPC pavement only decreases with the increase of loading speed. And the dynamic response curve of strain has three kinds of waveforms, and shows three kinds of changing characteristics with the increase of velocity. During operation period, the extreme value of the tensile strain of UHPC pavement is obviously larger than that of static load, but the dynamic response characteristics are consistent with those of dynamic load.