Abstract: The seasonal dynamics of soil microorganism, mini-animals, microbial respiration rate and biochemical effects, the relationships with the soil ecological factors were preliminarily studied, and the relationship between them were also analyzed in the wheat field of northeastern China. The results indicated that the soil microorganism, mini-animals, microbial respiration rate and biochemical effects have obvious seasonal variation in which the biggest values of the soil bacteria, actinomyces, hydra-nematoda, microbial respiration rate, cellulose decomposing rate, nitrogen fixing, organic phosphorus transformation, nitrification, ammonification and microbial respiration rate were in July, the fungus, arthropod collembola and inorganic phophorus transformation in June, the arthropod acarina was in the April and August, and the biggest values of soil inferior groups was in August, respectively. In 6 environmental factors, the soil temperature, water content, hydrolytic nitrogen, effective phosphorus and active organic matter, except pH, affected soil microorganism, mini-animals, microbial respiration rate and biochemical effects in different degree. In the fluctuating relationships between the soil bacteria, funguses, actinomyces and the soil mini-animals, except the soil arthropod collembola and the inferior groups, arthropod acarina and nematoda had bigger interdependent relationship. The soil microorganism and mini-animals contributed to the soil biochemical effects in different degree.