The invention discloses an MEMS Fabry-Perot cavity tunable filter. The MEMS Fabry-Perot cavity tunable filter is characterized by comprising a thermal-insulation external box (1), a sealed internal box (2), thermal-insulation materials (3) filled between the thermal-insulation external box (1) and the sealed internal box (2), damping materials (4) surrounding the sealed internal box (2), a metal fixed base (5) fixed on the undersurface of the sealed internal box (2), an incidence end double optical fiber contact pin (6), an incidence end collimating lens (7), a first heating power resistor (8), an MEMS Fabry-Perot cavity chip (9), a second heating power resistor (11), an outgoing end collimating lens (12), an outgoing end double optical fiber base pin (13) and a thermal resistor (10), wherein the incidence end double optical fiber base pin (6), the incidence end collimating lens (7), the first heating power resistor (8), the MEMS Fabry-Perot cavity chip (9), the second heating power resistor (11), the outgoing end collimating lens (12) and the outgoing end double optical fiber base pin (13) are fixed on the metal fixedseat (5), and the thermal resistor (10) is fixed on the MEMS Fabry-Perot cavity chip (9). The MEMS Fabry-Perot cavity tunable filter has the advantages of being small in size, fast in tuning, continuously-adjustable, high in fineness, narrow in bandwidth, wide in free spectral domain and tuning range, good in thermal stability, low in cost and the like.