The invention relates to a weak coupling resonance type micro-accelerometer with adjustable sensitivity. The weak coupling resonance type micro-accelerometer comprises a first mass block structure, asecond mass block structure and a resonance structure. The resonance structure is connected with the first mass block structure and the second mass block structure. The resonance structure includes afirst sensitive resonator, a second sensitive resonator, a coupling resonator and a sensitivity adjusting resonator, wherein the first sensitive resonator, the second sensitive resonator, and the coupling resonator have the same voltages. The first mass block structure includes a first mass block, a first fixed anchor point and a first elastic beam. The second mass block structure includes a second mass block, a second fixed anchor point and a second elastic beam. According to the invention, the limit sensitivity of the accelerometer is substantially improved through a three-degree-of-freedomweak coupling structure design and a modal localization principle for measuring an amplitude ratio; a resonator is additionally added based on the original design and the sensitivity of the accelerometer is adjusted by adjusting the electrostatic coupling negative stiffness between the resonator and the other two resonators, so that the measuring range is expanded by more than 50 times. Therefore,the weak coupling resonance type micro-accelerometer is suitable for a working scene with a very large acceleration change range.