Stable isotope technology is a very effective method for ecological research, and the stable nitrogen (N) isotope (δ¹⁵N) is widely used to investigate food chains and food webs in ecosystems. In this study, δ¹⁵N was used to analyze the trophic level of soil macrofauna in three artificial protection forests. The forests selected for this study belonged to three North Shelterbelts located in the Daowai and Acheng districts of Harbin, Heilongjiang Province. The total N and δ¹⁵N of 12 soil macrofauna samples were investigated in the three sample forests in September 2010 and the corresponding values in soil, leaf litter and fine plant roots were also determined. The results showed that the δ¹⁵N values of the soil macrofauna in each sample spanned a large range; between 2‰ and 6.40‰ in Wanbao, Daowai district, between -0.50‰ and 4.10‰ in Yangshu, Acheng district, and between 4.20‰ and 9.96‰ in Pingshan, Acheng district. The average values of δ¹⁵N in the three samples varied greatly; 5.34‰, 1.88‰ and 8.45‰ in WanBao, Yangshu and Pingshan, respectively. Statistical analysis showed that the δ¹⁵N of soil macrofauna under different conditions was significantly different (F=38.067, P<0.001) while the total N values of the macrofauna, soil, fine roots and leaf litter had no obvious difference (F=0.190, P=0.828) in the three plots. Correlation analysis showed a significant positive correlation of the total N values in the three samples. This indicates that the environmental differences had no influence on the total N content of the soil macrofauna. The correlation analysis showed that the δ¹⁵N values of the soil macrofauna had an obvious correlation with the δ¹⁵N values of the soil, fine roots and leaf litter; the correlation coefficients were all >0.6 (P < 0.05 or P < 0.01). However, the δ¹⁵N values had no correlation with the total N content or their correlation coefficients[(r=0.571 (P=0.026), 0.295 (P=0.285) and 0.404 (P=0.135) in Wanbao, Pingshan and Yangshu, respectively)].This research shows that the δ¹⁵N value of the environmental factors is an important element affecting the δ¹⁵N values of the soil macrofauna while the total N content of the soil macrofauna has no effect on the δ¹⁵N value. The different soil macrofauna of the three sample plots had specific correlations between the δ¹⁵N value of the soil macrofauna, and the correlation coefficients [r= 0.819 (Pr= 0.771 (Pr=0.466 (Pδ¹⁵N analysis could be used to determine trophic levels. Tipulidae larvae were selected as the primary consumer with 2.3‰ as the enrichment per trophic level to analyze the trophic level of the 12 soil macrofauna. The result showed that the trophic levels of the 12 soil macrofauna were from the second to the fourth level in the soil ecosystem. The animals in the low trophic levels mainly included Tipulidae larvae, Lumbricidae and Scarabaeidae larvae. The higher trophic levels had Scolopendromorpha, Staphylinidae adult stage, Elateridae adult stage and Enchytraeidae. The trophic positions of the same soil animals were diverse in different sample plots because the soil animals were in different feeding situations in different samples. Furthermore, the low classification rank was an important reason for the large differences in trophic level.