A high step-up DC-DC converter with active switched LC-network is proposed in this paper, which can be used in the photovoltaic system as the front-end stage to generate the required DC bus voltage. Based on the transformerless DC-DC converter with an active switched inductor (ASL) network, this proposed converter introduces an active switched capacitor (ASC) network, where only one capacitor and one diode are added, while the voltage gain is efficiently increased by a compound of ASL and ASC networks. The structure of the proposed converter is simple and voltage stresses on the additional diode and capacitor are low. In addition, unlike other voltage-boosting structures that utilized switched capacitor, the proposed converter avoids the extreme instantaneous currents of capacitor. The detailed analysis of the proposed converter and performance comparison with recently published ASL network-based converters are presented. Finally, a 100 W, 20/200 V prototype circuit is operated to verify its performance.