Abstract: In order to solve the problem of surplus corn stalks in the northeast region, this study used the straw speed rot agents prepared in laboratory for composting, and studied for the dynamic change of microbial flora and effective elements during composting process. This study sampled the samples with the method of timeshare and place share during the 40 d compost, recorded the change of temperature and pH, retained the samples with the method of quartering. Then, this study detected the dynamic change of the microbial flora and effective elements by plate notation and chemical methods. The results showed that: the pH and temperature changes of the experimental group, which was applied with mixed inoculants, could accelerate the straw decomposition and could significantly improve the number of microorganisms. The numbers of microorganisms in experimental group and CK2 group were higher than CK1 for one order magnitude, while the experimental group was higher than CK2 group for 30%. A lot of the propagation of microorganisms could significantly promote composting. Compost valid element content in the early, middle and late had significant changes in the accumulation of a large number of effective elements in the composting process. The group inoculated microorganisms composite agents could effectively promote the speed of straw humiliation, and enable the effective elements accumulated massively.