Abstract: Under the influence of global warming, floods and droughts often occur in summer over northeastern China, resulting in serious consequences to human and natural systems. However, the current seasonal prediction of summer precipitation over northeastern China is still low and far from satisfying the needs of disaster prevention and reduction. The precipitation during the rainy season in northeastern China is primarily concentrated in midsummer (July and August), and its interannual variability is comparable to that of interdecadal variability. The focus of this study is on examining the predictive role of the interannual variability of soil temperature in the interannual variability of midsummer precipitation over northeastern China. The results revealed a substantial negative correlation between the interannual variability of midsummer precipitation over northeastern China, the interannual variability of spring soil temperature over central and Eastern Europe, and a significant positive correlation with the interannual variability of spring soil temperature over eastern Qinghai Tibet Plateau and northeastern West Asia. The abnormal soil temperature in the key areas in spring relates to the abnormal soil temperature in the downstream region during the midsummer, thereby causing abnormal atmospheric circulation in East Asia during the midsummer. Furthermore, the upper-level westerly jet is strong and northward, and the western Pacific subtropical high is northward, leading to elevated water vapor convergence and upward movement over northeastern China, giving rise to increased precipitation in the midsummer. A seasonal prediction model for the interannual variability of spring soil temperature over central and Eastern Europe, eastern Qinghai Tibet Plateau, and northeastern West Asia was constructed to predict the interannual variability of summer precipitation over northeastern China. Moreover, the TCC (Time Correlation Coefficient) of the leave-one-out cross-validation could reach a maximum of 0.64, and hindcast during 2012–2021 could reach a maximum of 0.78 in the GLDAS-Noah, ERA5, and CRA/Land datasets, demonstrating that spring soil temperature plays a crucial role in predicting the interannual component of midsummer precipitation over northeastern China. This study offers a scientific basis for enhancing the prediction of summer precipitation over northeastern China to be easily applied to actual predictions.