Disclosed in the invention is a wired-and-wireless-optical-transmission-based double-polarization differential quadrature phase shift keying access apparatus comprising a plurality of phase modulators, a polarization beam combiner, free-space optical communication equipment, a polarization beam splitter, a plurality of couplers, a plurality of Mach-Zehnder delay interferometers, a plurality of photoelectric detectors and a plurality of Bessel low-pass filters. Two paths of differential quadrature phase shift keying optical signals are coupled to one single-mode fiber and transmission is carried out by an FSO device; and a downlink rate is increased by using a polarization multiplexing technology. Compared with the non return to zero code and differential phase shift keying signal, the DP-DQPSK signal has high frequency spectrum efficiency. After testing, the downlink transmission rate of the DP-DQPSK signal can reach 10Gb/s at a 50-km SMF-28 fiber and a 100-m wireless optical channel and the error rate can be lower than 10 <-6>. Compared with the existing long-distance telecommunication transmission system, the provided apparatus has advantages of simple structure and low cost.