Addressing the issues of low precision in short baseline time-difference direction finding, ambiguity in long baseline phase-difference direction finding, and the difficulty of traditional microwave technologies to meet the long-distance transmission requirements for distributed deployment of electronic warfare equipment, a distributed long-distance single-baseline high-precision direction finding technology based on microwave photonics combining time-difference and phase-difference is proposed. This technology employs direct modulation mode microwave photonic transmission equipment, overcoming the impact of time-difference and phase-difference variations caused by long-distance transmission of microwave signals, ensuring stable transmission of microwave photonics over long distances. Furthermore, an improved time-difference surface fitting interpolation method is adopted to resolve the phase-difference ambiguity issue. Simulations and experimental tests have verified the feasibility of this technology for implementing high-precision distributed long-distance single-baseline direction finding.