The spin-dependent electron transport properties of quantum waveguide systems with attached stubs in the presence of Rashba spin-orbit coupling (SOC) by recursive Green function (RGF) method are theoretically studied. In the single-stub Rashba SOC quantum waveguide system, the dip-like structure and valley-like structure emerge in the charge conductance spectra due to the stub-induced potential well and SOC-induced potential well. In addition, the peaks of the dip-like and valley-like structure can be controlled by changing the strength of Rashba SOC. At the same time, a series of resonant peaks and dips occur in the charge conductance and spin conductance, at the energies that correspond to the quasi-bound states in the stubs. Moreover, due to the presence of multiple modes and the mode-mixing effect as the number of stubs increases, there are some mini-bands exist in the charge conductance and spin polarization. However, the quantization plateau is gradually recovered, a set of resonances occurs in the charge conductance and spin conductance at the threshold of every transmitted mode when the system is in the presence of an electromagnetic field.