The controllable growth of large area band gap engineered-semiconductor nanowires (NWs) with precise orientation and position is of immense significance in the development of integrated optoelectronic devices. In this study, we have achieved large area in-plane-aligned CdSxSe1-x nanowires via chemical vapor deposition method. The orientation and position of the alloyed CdSx-Se1-x NWs could be controlled well by the graphoepitaxial effect and the patts of Au catalyst. Microstructure characterizations of these as-grown samples reveal that the aligned CdSxSe1-x NWs possess smooth surface and uni-form diameter. The aligned CdSxSe1-x NWs have strong photoluminescence and high-quality optical waveguide emission covering almost the entire visible wavelength range. Furthermore, photodetectors were constructed based on individual alloyed CdSxSe1-x NWs. These devices exhibit high performance and fast response speed with photoresponsivity ～670 A W-1 and photoresponse time～76 ms. Present work provides a straightforward way to realize in-plane aligned bandgap engineering in semicon-ductor NWs for the development of large area NW arrays, which exhibit promising applications in future optoelec-tronic integrated circuits.