In this study, we theoretically investigate the high-order harmonic and isolated attosecond pulse generation with respect to the helium ion in the spatially inhomogeneous chirped field. The results demonstrate that the harmonic spectral cutoff of the spatially inhomogeneous chirped field is significantly extended when compared with the harmonic spectra generated by the single inhomogeneous field and the chirped field. Subsequently, an ultrabroad supercontinuum with a bandwidth of 1073 eV is successfully obtained. Furthermore, the spatiotemporally synthesized field can suppress a long path and select a short path to efficiently contribute to supercontinuum generation. Therefore, an isolated 13 as pulse is directly generated by superposing a wide range of continuous harmonics. Finally, a single attosecond pulse with pulse width of 7.4 as can be easily obtained by adjusting the chirp parameter.