The electrochemical CO2 reduction reaction (ECO2RR) has the capability to convert CO2 molecules into high-value products, offering a feasible pathway aligned with carbon cycling and emission reduction. Nevertheless, significant efforts are required to achieve highly active and selective catalysts tailored for specific products. Herein, a facile synthesis route is proposed, wherein copper, phosphorus, and carbon precursors are mixed and subsequently calcined at different temperatures to obtain a series of copper-based catalysts (CPC-300, 500, 700) containing various copper components with different phases and oxidation states. And further performance tests show their differentiated product distributions. Specifically, CPC-300, which contains more high-valence Cu, is more inclined to produce C2 products, while CPC-700 possessing low-valence Cu as its phase is more keen to produce C1 products. In particular, the CPC-700 catalyst presents a high FECH4 of 52.2 % with a CH4 partial current density of −167.8 mA cm−2 at −1.447 V vs. RHE. Combining the results of in-situ Raman and electrochemical characterizations confirms the effect of valence state and composition on the adsorbed intermediates containing *CO and *H during the reaction. This work achieves the design and development of highly selective and active Cu-based catalysts from the strategies of valence state and component engineering.