A discharge plasma simulation based on a fluid model is carried out in order to investigate the effect of chemical reactions considered in the model on the reproducibility of electrohydrodynamic (EHD) force generation and gas heating processes in dielectric barrier discharge (DBD) plasma actuator. Single micro-discharges with positive and negative polarities are simulated utilizing two models with different reactions: simple model considering typical 6 reactions and model considering recombination in detail. There are no qualitative discrepancies in the characteristics of EHD force and heating power between two models, however; the composition of positive ion species is significantly different. In the detailed model, the dominant species is cluster ion (O4+) whose electron-ion recombination coefficient is quite high. In the positive discharge, secondary electron emission by positive ion bombardment decreases, resulting in the decrease in seed electrons. In the negative discharge, the rate of electron attachment decreases, and electrons and positive ions are lost rapidly due to the recombination. As a result, the recombination with cluster ions contributes to decrease in the positive EHD force and heating power in both positive and negative discharges.