AbstractPerovskite semiconductors have shown significant promise for photodetection due to their low effective carrier masses and long carrier lifetimes. However, achieving balanced detection across a broad spectrum—from X‐rays to infrared—within a single perovskite photodetector presents challenges. These challenges stem from conflicting requirements for different wavelength ranges, such as the narrow bandgap needed for infrared detection and the low dark current necessary for X‐ray sensitivity. To address this, this study have designed a type‐II FAPbI3 perovskite‐based heterojunction featuring a large energy band offset utilizing narrow bandgap tellurium (Te) semiconductor. This innovative design broadens the detection range into the infrared while simultaneously reducing dark current noise. As‐designed device allows for the detection of near infrared band, achieving a detectivity of 6.8 × 109 Jones at 1550 nm. The low dark current enables X‐ray sensitivity of up to 1885.1 µC Gy⁻¹ cm⁻2. First‐principles calculations confirm the type‐II band structure alignment of the heterojunction, and a self‐driven response behavior is realized. Moreover, this study have developed a scalable 40 × 1 sensor array, demonstrating the potential for wide‐spectrum imaging applications. This work is expected to advance the application of perovskite‐based wide‐spectrum devices.