We investigated the formation of the helical phase (H*) of chiral block copolymers polystyrene-b-poly(L-lactide) (PS-b-PLLA) using transmission electron microscopy, small-angle X-ray scattering, and wide-angle X-ray diffraction. In particular, the influence of solvent affinity for either block and the rate of evaporation on the morphology formed during solution-casting were examined. The evaporation rate was adjusted by changing the temperature for solution-casting, while the affinity between various solvents and PS or PLLA blocks were rationalized using Hansen solubility parameters. We find that good solvents for both blocks are necessary for the H* phase to form, while solvent removal rate together with solvent property affects the crystallization of chiral block, which influences the formation of the H* phase in a complicated manner. The H* phase can coexist with PLLA crystals. These findings broaden the parameter space for generating H* phase from PS-b-PLLA and aid in designing experiments to understand the mechanism underlying the formation of this unique morphology.