Optical devices based on alloying semiconductors offer a plethora of new possibilities for detection across a broad spectrum. Among these devices, nanowire‐based devices have gained much attention due to their remarkable specific surface area properties in terms of material synthesis, device structure, and performance. In this work, (BixIn1−x)2S3 nanowires are designed by controlling the ratio of Bi and In atoms. The atomic ratio directly affects the electronic band structure of the crystal, thereby further optimizing the performance of optoelectronic devices. According to the experimental results, Bi1.28In0.72S3 nanowire‐based photodetectors obtain the most excellent photoresponse performance. The typical device demonstrates a spectral response from deep ultraviolet (DUV 254 nm) to near‐infrared (NIR 1064 nm) and achieves a maximum dichroic ratio of photoresponse of 1.5 under polarization‐angle‐sensitive detection in the 266–808 nm range. It also exhibits a photoresponse of 10.1 A W−1 and a photodetectivity of 5.7 × 1010 Jones under 532 nm light irradiation. Additionally, the photodetector displays a fast response speed with a rise/fall time of 5/4.7 ms. Finally, “CSU” and puppy images produced by this device further demonstrate the effectiveness of alloying semiconductors in creating wide‐spectrum, high‐responsivity, fast‐response, and polarimetric‐sensitive photodetectors.