Soil macro-fauna play an important role in soil ecosystems. They are at the top of the entire food web and regulate the availability of resources for other animals by changing biotic or abiotic materials. Knowledge of soil macro-faunal guild characteristics is crucial to understanding soil food webs. On the Songnen grassland, located on the northeastern grassland area of China, above ground succession of vegetation can markedly change with soil fauna. The effect of this degradation on the structure and diversity of the below ground soil faunal guild is unknown. In the present study, an investigation of the composition, structure and diversity of the soil macro-faunal guild was conducted in the Songnen grassland with six successional stages (Leymus chinensis community; Leymus chinensis+Chloris virgata community, Chloris virgata community, Puccinellia distans community, Suaeda glauca community and Bare alkali-saline patch). Six observations were conducted from May to October 2005 and four samples in a 50 cm × 50 cm area were investigated in six successional stages each time. Hand collection methods were used to collect soil macro-fauna with soil macro-faunal guilds subdivided based on their feeding habits. The results showed that macro-fauna were divided into four guilds based on their feeding habits, i.e., omnivore, herbivore, predator and detritivore. Omnivore and herbivore were the predominant guilds, accounting for 39.16% and 50.00% in term of the total individual and group numbers, respectively. Detritivore occurrence was rare. The correlations between individual and group numbers were not significant (P>0.05). In general, the Leymus chinensis community and Leymus chinensis+Chloris virgata communities had the largest number of individual and group number among the four guilds, whereas the bare alkali-saline patch was rare. Significant successional stage effects were recorded in individual and group numbers of herbivore, individual numbers of omnivore and individual and group numbers of detritivore (P<0.01). There were positive correlations between individual and group numbers of herbivore and detritivore at different successional stages (P<0.05). In the 0-10 cm and 20-30 cm depth, significant successional stage effects were recorded in the individual numbers of guilds, except predator (P<0.05 or P<0.01). In the 10-20 cm depth, significant successional stage effects were recorded in individual numbers of guilds, except detritivore (P<0.05 or P<0.01), and there were positive correlations between individual numbers of herbivore and detritivore at different successional stages (P<0.05). In the 0-10 cm depth, there were positive correlations between individual numbers of herbivore and omnivore at different successional stages (P<0.05), whereas, in the 20-30 cm depth, there were negative correlations between the individual numbers of the four guilds at different successional stages (P>0.05). The results of the different guilds diversity analysis showed successional stages had different influences on diversity. Significant successional stage effects were recorded in the Margalef index (D) of herbivore (P<0.01); the Shannon-Wiener index (H') of omnivore, predator and detritivore (P<0.01); the Simpson index (C) of omnivore and predator (P<0.01 or P<0.05); and the Pielou index (E) of omnivore and predator (P<0.01 or P<0.05). The similarity results showed that the similarities of guilds between the Leymus chinensis and bare alkali-saline patch are lower than the other successional stages. These results suggest that different degenerative succession stages of Songnen grassland can significantly reduce taxonomic diversity and structural complexity within guilds of soil macro-fauna.