Ongoing research on the sensitivity and integration of refractive index-based biosensors has resulted in significant advancements. Here, the study presents an enhanced surface plasmon resonance biosensor that integrates imaging technology and features dual-parameter interrogation (intensity and phase) with guided mode coupling. By depositing a silica-waveguide-layer on a metal-layer, two-mode coupling is established to generate a high Q resonance and induce a phase mutation. The sensing performance experiment demonstrated a phase sensing sensitivity of 1.1 × 105 degree RIU−1, Q-value of the resonant peak up to 314, and figure of merit of 300 RIU−1, superior to most standard plasmonic sensors. An in-line phase-polarization modulation scheme combined with imaging technology is proposed to extract the resonant phase carrying refractive index information. Additionally, a pair-prism module is designed to optimize the sensing system configuration. Meanwhile, dual-parameters interrogation including the intensity and phase are demonstrated, which offers potential for complementary and multi-sensing fusion applications. The intensity interrogation also shows a considerable sensitivity of 7.2 × 104 a.u. RIU−1. Furthermore, it is combined with microfluidic chip to detect of alpha-synuclein protein closely related to Parkinson's disease, and the limit of detection can reach 300 pg mL−1 level, which indicated a considerable potential for high-throughput diagnosis application.