Optical-based microwave electric field detection has emerged as a research hotspot due to its advantages of high spatial resolution and immunity to electromagnetic interference. However, existing techniques are often limited by their sensitivity or reliance on specialized fluorescent materials. Gold nanobipyramids (AuNBPs), serving as nanoprobes with tip-enhancement effects and a well-defined three-level system, exhibit high sensitivity in their two-photon photoluminescence (TPPL) process to phase perturbations and plasmon resonance changes induced by microwave fields. By establishing a quantitative mapping model between microwave intensity and TPPL signal strength, we achieved an absolute measurement of microwave field strength with a spatial resolution that breaks the 100-nanometer barrier. Through comparative analysis of microwave responses under different pulse delays, we reveal that the microwave field primarily modulates TPPL intensity by interfering with the coherent excitation pathway. The most significant response of TPPL intensity to microwave power was observed near the zero-delay point, where the quantum coherence is strongest.