The present disclosure relates to the field of communication technologies, and more particularly, to an adjustable coupling device and a radio frequency communication device. The adjustable coupling device includes a coaxial transmission line for transmitting signals across the two terminals thereof and a coupling body for sampling the signals via coupling. The adjustable coupling device further includes a coupling cavity formed on the outer surface of the coaxial transmission line; a printed circuit board on which the coupling body is disposed, the printed circuit board capping the coupling cavity to seal the coupling body within the coupling cavity; a tuner, disposed through the printed circuit board, where the lower end of the tuner extends into the coupling cavity, and the tuner can be moved up and down to change the depth thereof extended into the coupling body so as to change the electromagnetic field distribution within the coupling cavity. In this way, the present disclosure has a simple structure and thus eliminates the influence on the coupling device derived from the structure and the machining accuracy and assembly techniques of printed circuit board, with simple tuning means and high reliability.