The 22 heavy rain days that occurred over Northeast China during July-August 2010 were divided into three types according to their differences in synoptic system and precipitation area. Based on an analysis of the water vapor transport and budget using a Eulerian method, the characteristics of the major water vapor passages and their contribution ratios to water vapor transportation were studied using NCEP/NCAR reanalysis data and the HYSPLIT v4. 9 model. The results showed that there are three major water vapor passages that act to affect heavy rain over Northeast China. One is the water vapor transport of the southeast moisture current along the edge of the western Pacific subtropical high. Another is the water vapor transport of the southwest moisture current that originates from the north of the South China Sea. And the third is the water vapor transport of the northwest flow, which originates from the westerlies. During the first type of heavy rain, there is little difference in value between the transportation coming from the western Pacific Ocean passage and that from the South China Sea passage;they are both important, and can each account for up to 87. 4% of the total moisture transport. During the second type of heavy rain, the moisture transport path is shifted slightly to the east compared with that of the other types of heavy rain. The water vapor transport of the western Pacific Ocean passage can account for close to 70% of the total transportation. During the third type of heavy rain, the water vapor transport of the northern passage becomes prominent, although the moisture transport of the western Pacific Ocean passage also plays a leading role in the total transportation. The moisture of the western Pacific Ocean passage has smaller losses during transportation and is mainly transported to levels beneath 850 hPa. The moisture of the South China Sea passage has larger losses during transportation and is mainly transported to levels above 850 hPa, as is the moisture of the northern passage.