The invention discloses a planar EMI filter integrating common mode inductors, differential mode inductors and differential mode capacitors. The planar EMI filter comprises a tank type magnetic core, a panel magnetic core, common mode capacitors, integrated inductor-capacitor structures and leakage inductance layers. The common mode capacitors and the integrated inductor-capacitor structures form inductor-capacitor units. Every two inductor-capacitor units are isolated through the corresponding leakage inductance layer and are symmetrically arranged on the two sides of the corresponding leakage inductance layer. Each common mode capacitor and each integrated inductor-capacitor structure are respectively provided with a ceramic substrate and a spiral coil, wherein the ceramic substrate is provided with a plurality of via holes, and the two ends of the spiral coil are both connected with the conducting via holes. Each leakage inductance layer is provided with a plurality of insulating via holes corresponding to the via holes in each ceramic substrate. Every two common mode capacitors are connected with each other through the corresponding conducting via holes. Each common mode capacitor and the corresponding integrated inductor-capacitor structure are connected with each other through the corresponding conducting via holes. Every two integrated inductor-capacitor structures are connected with each other through the corresponding conducting via holes. By the adoption of the planar EMI filter, seamless connection between modules is achieved, parameters of the common mode inductors, parameters of the differential mode inductors and parameters of the differential mode capacitors are integrated, and the problems that in the prior art, an existing filter is large in magnetic leakage, large in size and poor in filtering effect are solved.