The invention discloses an impedance matching network and a self-adaptive impedance matching device and a method thereof, the impedance matching network is composed of a variable capacitor and a variable inductor, the variable capacitor is composed of at least two capacitors connected in parallel, the capacitance values are gradually reduced, and the maximum capacitance value is determined by the variable capacitance change range; the variable inductor is composed of at least two inductors connected in series, inductance values are gradually decreased, and the maximum inductance value is determined by the variable inductor change range. The self-adaptive impedance matching device comprises a sampling module, the impedance matching network and a controller, the controller executes calculation of load impedance after receiving a sampling signal, so that the characteristic parameters of the impedance matching network corresponding to the impedance matching state are determined, the impedance matching network is adjusted according to the characteristic parameters, and impedance matching is achieved. The impedance matching network and the adaptive impedance matching device have the advantages of wide matching range, high matching precision and flexibility, high reliability, low cost, fast response, simple implementation mode and the like.