The invention discloses a novel D-shaped structured photonic crystal fiber sensor based on surface plasma resonance. The sensor comprises a base, air holes and gold nano-films, wherein a central air hole is formed in the center of the base, the air holes include small air holes and D-shaped big air holes, the small air holes are arranged around the central air hole, the central air hole and the neighborhood form a photonic crystal fiber core, that is, the region defined by the small air holes forms the photonic crystal fiber core, the small air holes are arranged in a triangle or regular polygon, one D-shaped big air hole is arranged outside each side of the triangle or regular polygon, straight line surfaces of the D-shaped big air holes correspond to the sides of the triangle or regularpolygon, the straight line surfaces of the D-shaped big air holes are plated with the gold nano-films, and the D-shaped big air holes can be expanded infinitely. Through the novel D-shaped structuredphotonic crystal fiber sensor, the uniformity of metal nanometer coating and filling of to-be-tested liquid are effectively realized, and it is convenient to realize high-sensitivity sensing detection.