In order to study the influence upper equipment load spectrum from upper spring mass, six freedom vibration signals on the vehicle was measured in a Chinese PG. The signals were the acceleration-time histories. Test was made under 3 loads conditions, which represent 3 types of upper spring mass. After filtering, rainflow counting, fatigue damage caused by the load spectrum was got. Result shows there were great difference in distributions between different direction load spectrums; spring upper load made small influences for the character of load spectrum at the same direction. The upper spring mass became larger, the equipment suffers more damage.