In order to explore the processing parameters for the continuous production of double-based spherical propellants with particle sizes in the range of hundred microns， a Co-axial flowing microfluidic installation was used to process the dispersed phase of a 10 % double-based propellant solution and prepare the double-based spherical propellants with a controllable particle size in the range of 400-700 μm. The effects of two-phase flow ratio（Q_c/Q_d） and chip size on the morphology and particle size of double-based spherical propellants were investigated. Moreover， the morphology， particle size distribution， and constant volume combustion performance of samples were characterized using scanning electron microscopy， optical microscope， and closed bomb test，respectively. Results show that， the median particle size （D₅₀） of the samples prepared into the same type of chip increases first and then decreases with the decrease of two-phase flow ratio. As the internal diameter of the continuous phase or the dispersed phase channel increases， the D₅₀ of the samples obtained at the same two-phase flow ratio increases successively. When the internal diameter of the continuous phase and the dispersed phase channels are 2 and 0.85 mm， and the two-phase flow ratio is 200.00， the resultant sample displays high monodispersity， smooth surfaces， dense inside， regular spherical shapes （average sphericity φ_K=0.949） and narrow size distribution （span=0.09）. Its D₅₀ is 539.94 μm， and the average particle density is 1.601 g·cm^-3. In the closed bomb test， the pressure-time curve shows that the samples with two varied packing densities （Δ₁=0.12 g·cm^-3， Δ₂=0.20 g·cm^-3） can burn stably， and the dynamic vivacity-relative pressure curve follows the regressive burning law of the dense spherical propellants.