Abstract: A frequency detection method based on synchronous oscillation of resonators, and a tilt sensor using the frequency detection method are disclosed. The sensor includes a detecting unit and a synchronization unit which are respectively disposed in a first oscillating circuit and a second oscillating circuit for forming two self-excited oscillators. The detecting unit and the synchronization unit are electrostatically coupled through a plate capacitor to allow a weak synchronous current to pass through, which affects and reduces phase noise of the self-excited oscillator formed by the detecting unit, thereby greatly improving the frequency stability thereof and simultaneously reading out a natural frequency thereof through a frequency counter. Three detecting units are respectively evenly distributed at a periphery of a hexagonal mass block through magnifying beams. The mass block is configured to sense a gravitational acceleration.