Using 1979–2020 ERA5 daily reanalysis data, this paper analyzes the statistical characteristics of blocking and its modulation on surface air temperature anomalies (SATA) during stratospheric northern annular mode events (NAMs). The results show that the four blocking highs in the northern hemisphere tend to occur in different stages of NAMs. Greenland blocking (GB) and North Pacific blocking (NPB) occur more frequently in the development stage of positive NAMs and the decay stage of negative NAMs. Ural blocking (UB) tends to occur in the decay stage of positive NAMs and the development stage of negative NAMs. The Atlantic-Europe blocking (AEB) is more likely to occur in the decay stage of both positive and negative NAMs. Although the number of days with blocking high is far less than that without blocking high during NAMs, the blocking high has a significant modulation effect on the spatial pattern of SATA related to the NAMs. When GB occurs during positive NAMs, the SATA in Eurasia changed from “overall warm” or “North warm-South cold” to “North cold-South warm” in the extratropics, while the SATA in North American changed from the “overall cold” or “North cold-South warm” to “North warm-South cold”. The UB in the decay stage of negative NAMs can not only reverse the “North cold-South warm” SATA pattern to “North warm-South cold” pattern in Eurasia, but also lead to the SATA pattern in North American changing from “North warm-South cold” to “South warm-North cold”. However, the modulation effect of AEB and NPB on the spatial patterns of SATA in most stages of NAM is not significant, that is, the spatial patterns of SATA is mainly dominated by NAMs. Under the influence of NAMs and the modulation of blocking high, Eurasia is colder and North America is warmer in mid latitudes from the peak stage of positive NAMs to the developing stage of negative NAMs, while it is the opposite from the decay stage of negative NAMs to the initial stage of positive NAMs. The dominant patterns of SATA in Eurasia and North America tend to the South-North dipole pattern between mid- and high- latitudes during NAMs. These conclusions are verified by Monte Carlo random sampling test.