Fluids containing polymers are frequently utilized in the chemical industry and exhibit shear-thinning characteristics. The flow distribution of non-Newtonian fluids in parallelized microchannels is a key issue to be solved during numbering-up. Numbering-up means increasing the number of parallelized microchannels. In this study, a high-speed camera is used to explore the distribution of fluid flow as well as the uniformity and stability of droplets in conceptual asymmetrical parallelized microchannels. Cyclohexane and carboxymethylcellulose sodium (CMC) aqueous solutions are used as the continuous phase and dispersed phase, respectively. The effects of fluctuation of pressure difference around the T-junction, the hydrodynamic resistance in microchannels, and the shear-thinning property of fluids on flow distribution and droplet formation are revealed. The uniformity and stability of droplets in microdevices with various cavity settings are compared, and an optimal configuration is proposed. Finally, prediction models for the flow distribution of shear-thinning fluids in asymmetrical parallelized microchannels are established.