The invention discloses an integrated DC solid state power controller and a fault decision-making diagnosis method. The controller comprises a power board and a digital control board, wherein the power board is mainly responsible for system state detecting, conditioning, signal uploading and SSPC (Solid State Power Controller) driving and protection control; and the digital control board integrates related circuits for arc fault detection and cable fault detection and location, detects a conditioned system state signal based on multiple sensors, completes local fault diagnosis for the conventional SSPC such as fixed-time-lag power supply overvoltage-undervoltage fault protection, BIT self-checking of the SSPC, inverse-time-lag overload protection and additional local fault diagnosis such as system arc fault detection and cable fault detection and location in a concurrent manner in an FPGA main control module, and finally realizes decision-making diagnosis and health management for thesystem state based on a multi-source technology integration technology. The integrated DC solid state power controller can realize the enhanced system fault detection and health management ability, and improves the system safety, reliability, testability and maintenance.