The present invention provides a fan blade adjusting device. With the fan blade adjusting device of the invention adopted, the technical problems of complicated structure, high cost and inconvenient operation of an existing adjusting device can be solved. The fan blade adjusting device comprises a fan blade and a base. The fan blade adjusting device is characterized in that the fan blade adjusting device further comprises a telescopic adjusting mechanism, an angle adjusting mechanism and a driving mechanism; the telescopic adjusting mechanism includes slide rails, a slide seat, a first screw rod and a first screw rod seat, wherein the first screw rod is supported on the first screw rod seat and is in threaded connection with the slide seat; the angle adjusting mechanism includes a second screw rod seat and a second screw rod, wherein the second screw rod is in threaded connection with the second screw rod seat; and the driving mechanism includes a transmission shaft supporting seat, a transmission shaft, a servo motor, a driving gear, a first driven gear, a second driven gear and a shifting rod, wherein the driving gear is slidably connected onto the transmission shaft and rotates synchronously with the transmission shaft, the first driven gear is fixed at an end portion of the first screw rod, the second driven gear is fixed at an end portion of the second screw rod, and the shifting rod can drive the gear to move along the transmission shaft and to be engaged with the first driven gear or the second driven gear.