Photonic integrated circuits serve as essential platforms in quantum science, particularly in quantum communication and quantum computing, where linear high-performance single-photon detector arrays are required. Superconducting nanowire single-photon detectors (SNSPDs) are known for their outstanding overall performance and compatibility with on-chip integration, making them the preferred choice for quantum photonic applications. However, conventional SNSPD arrays face challenges such as increased readout complexity or reduced detection speed. Herein, we present an amplitude-encoded SNSPD array featuring single-channel readout and high-speed detection capabilities, demonstrating high-quality discrimination of 12 pixels. This detector can readily achieve proof-of-concept quantum random number generation, underscoring its promise for advanced quantum information applications.