[Objective] The tempo-spatial change characteristics of aerial and subaerial air relative humidity and its responses to temperature and precipitation were explored, to provide basis for the research of climate fluctuation process in Shandong Province.[Methods] Based on the radio sounding and land surface observation data of Shandong Province during 1960-2012, we used regression analysis, IDW, Mann-Kendall non-parametric statistical test and sensitivity analysis to analyze the change characteristics of relative humidity.[Results] The annual subaerial air relative humidity exhibited an obvious decreasing trend (p>0.05) from 1960 to 2012 at a rate of -0.23% per 10 a. In spring, autumn and summer, the values were -0.45%, -0.42% and -0.18% per 10 a, respectively. On the contrary, the relative humidity increased in winter with a rate of 0.10% per 10 a. In spatial, subaerial air relative humidity decreased from the eastern coastal area to the western inland area. However, with regard to the change rate, it is fast in eastern area and slow inland. The aerial air relative humidity had similar spatial change. From the costal to the inland, the decreases in mid and lower troposphere were more obvious than that in the upper troposphere. The seasonal variations could interpret the annual change with different proportions, having an order as:autumn > spring > winter > summer. For mid and lower troposphere, the seasonal contributions ranked as:autumn > winter > spring > summer; For upper troposphere, the rank was summer > autumn > winter > spring.[Conclusion] Sensitivity analysis showed that if drought index changes by 1% during 1960-2012, could induce aerial and subaerial air relative humidity to change by -1.55% and -1.96% respectively; accordingly, if temperature or precipitation changes by 1%, relative humidity will change by -0.15% to 0.09%.