Abstract: Elevated heat sources over the Tibetan Plateau (TP) and the Iranian Plateau (IP) have significant impacts on East Asian climate. Based on monthly mean surface heat fluxes extracted from the ERA-interim reanalysis data for the period of 1979 to 2011, surface thermal characteristics during boreal spring and summer over both TP and IP and their relationships were analyzed. The results show that the basic spatial and temporal characteristics of surface heat fluxes over TP and IP are different in the spring and summer, and surface heat fluxes in specific regions of these two plateaus exhibit different characteristics on interannual and interdecadal time scales. Over TP, surface sensible heat flux (SH) in the western part is stronger than that in the eastern part during the spring and summer, whereas the spatial distribution of surface latent heat flux (LH) is opposite with larger values in the eastern part. SH peaks in the spring and exceeds LH before the summer, but LH is larger than SH in the summer. On the interannual time scale, SH is negatively correlated with LH in western TP during the spring and summer, and SH anomalies over western TP can persist from spring to summer. On the interdecadal time scale, there is a significant difference in surface heat fluxes between eastern and western parts of TP. Springtime (summertime) SH over eastern TP exhibits a significant decreasing trend and experienced an interdecadal change in 1998 (2001), switching from positive to negative anomaly. However, springtime SH over western TP exhibits a significant increasing trend and experienced a negative-to-positive interdecadal change in 2003. The LH over eastern TP displays a significant decreasing trend only in the spring and exhibited a positive-to-negative interdecadal change in 2003. The LH over western TP exhibits a significant decreasing trend in both the spring and summer and experienced an interdecadal change at the beginning of the 21st century, switching from positive to negative anomaly. Over IP, both SH and LH are uniformly distributed during the spring and summer. SH peaks in the summer, LH is strong in the spring but weak in the summer, and it is smaller than SH all year round. SH over IP is stronger than SH over TP in each season. On the interannual time scale, spring and summer SH (LH) anomalies over the entire IP are uniformly positive (negative). There is a significant negative correlation between SH and LH over IP. SH and LH anomalies over IP can persist for quite a while. A significant difference is found in the interdecadal variability of surface heat flux between northern and southern parts of IP. The spring and summer SH (LH) over northern IP exhibits a significant increasing (decreasing) trend and experienced an interdecadal shift in the end of the 20 century, when the anomaly of SH (LH) switched from negative (positive) to positive (negative). There is no significant trend in SH and LH over southern IP during the spring and summer. However, SH over southern IP in the spring and summer experienced a negative-to-positive interdecadal change, while springtime LH experienced a positive-to-negative interdecadal change at the end of the 20th century. The relationship between surface heat fluxes over these two Plateaus is as follows:SH over IP is positively correlated with SH over western TP and is negatively correlated with SH over eastern TP in the spring; LH over IP is positively correlated with LH over eastern TP in the spring; SH over IP in the spring is negatively correlated with SH over eastern TP in the subsequent summer.