This application discloses a planar inductor. The planar inductor includes a first inductor module and a second inductor module that are connected in parallel. A direction of a magnetic line of the first inductor module is opposite to a direction of a magnetic line of the second inductor module, so that the magnetic lines can form a self-close loop in the planar inductor, and impact of a far magnetic field generated by the inductor on the outside, especially a nearby inductor, can be greatly reduced, thereby reducing crosstalk between the inductors, that is, reducing a phase noise, and increasing a Q value of the inductor. In addition, this application further provides a semiconductor chip that includes the planar inductor.