A one-dimensional micro-bending vector sensor based on two-mode interference has been introduced. This device was fabricated by lateral offset splicing a piece of six-air-hole grapefruit microstructure fiber (GMF) with single mode fiber (SMF). Variation of effective mode index occurred by micro-bending was investigated in simulation and experiment. This device exhibits micro-bending sensitivities of 0.441 nm/m(-1) and -0.754 nm/m(-1) at 0° and 180° bending orientations, respectively. Moreover, this sensor is immune to surrounding refractive index (SRI) and presents a low crosstalk of temperature.