The invention provides a directional coupler. The directional coupler includes a transmitting port, an output port, an isolation port, a coupling port, a first inductor connected between the transmitting port and the output port, and a second inductor connected between the coupling port and the isolation port, wherein the inductance of the first inductor is less than that of the second inductor, at least the second inductor is a lumped element. According to the invention, the directional coupler can save area, is flexible to use, and can be formed on a chip or a substrate. Compared with a distributed passive structure, this structure has low demand for design of the passive structure, the flexibility is greatly enhanced, and the high integration density and the low cost can be easily realized.