We demonstrate emergence of both the chiral soliton lattice and skyrmion lattice and investigate their magnetic-field variation in the strained Cu2OSeO3 thin plate by means of small-angle resonant soft x-ray scattering. The tensile strain stabilizes a helical spin structure with the modulation vector along the strain direction. Consequently, when increasing the field perpendicular to the modulation vector, it undergoes large shrinkage and higher-order diffraction peaks are also observed, which is in accord with a typical feature of the chiral soliton lattice. The skyrmion lattice also appears in the presence of tensile strain but is elongated along the strain direction in reciprocal space. The magnetic-field dependence of the modulation vector along the strain direction agrees with the theoretical model quantitatively, while that along other directions does not. The agreement, however, becomes worse at lower temperatures, which may be attributed to the large potential barrier for skyrmion annihilation.