Using the lowest water level data of the mainstream of Songhua River from 1949 to 2003 at Harbin, an analysis is made of the causes and variation regularities of low-level water for the typical low water-level years, the correlation between the water levels of Songhua River and the rainfall of Songhua River, Nenjiang River, etc., and the relation with La Nina, El Nino, sunspot activities, etc. Based on the total areal rainfall of the Songhua River, Nenjiang River, and the second Songhua River from July to November and the highest water level of the Songhua River mainstream of the previous year at Harbin, the lowest water levels of the Songhua River at Harbin from 2004 to 2013 are predicted. Utilizing the periodical analysis of variance and the method of mean generation function, predictions are made of La Nina, El Nino, sunspots and the monthly mean areal rainfall over the Songhua River, Nenjiang River, and the second Songhua River regions from 2004 to 2013. Hereby, the lowest water level predictions of Songhua River at Harbin from 2004 to 2013 are revised.