Multi-functionality of land use is the result of the process of land utilization according to the socioeconomic goals, which is the key to ensuring the coordinated development of the socioeconomic and ecological environments. By constructing a social-economic-ecological multi-functional land use evaluation indicator system, this article comprehensively examines the multi-functionality of land use from 1990 to 2013 in Northeast China, which aims to explain the spatiotemporal patterns of multi-functionality of land use in the area. The results show that functional values of land use showed an upward trend during 1990-2013 in Northeast China, but the growth rates differed. The development levels of land use functions in Heilongjiang, Jilin, and Liaoning Provinces were in an ascending order, and the average annual growth rates were 2.976%, 2.725%, and 2.261%, respectively. The social function values of Heilongjiang and Jilin Provinces increased with some fluctuations, but Liaoning Province showed a periodical change. The economic function values of Heilongjiang Province increased, but that of Jilin and Liaoning Provinces showed an overall upward trend yet fluctuated in 2000 to 2005. The ecological function values of Heilongjiang and Jilin Provinces were stable at the beginning of the period then showed an increasing trend with some fluctuations, whereas in Liaoning Province it always showed greater volatility. Land production and transportation, which are important parts of the economic function, had a great impact on the land use functionality of the three provinces in Northeast China. Economic and social factors had a greater impact on the multi-functionality of land use in Heilongjiang and Jilin Provinces, while ecological factors played a smaller role. But in Liaoning Province, economic, social, and ecological factors all had important impacts on the multi-functionality of land use.