Copper-based catalysts are widely explored in electrochemical CO2reduction (CO2RR) because of their ability to convert CO2into high-value-added multicarbon products. However, the poor stability and low selectivity limit the practical applications of these catalysts. Here, we proposed a simple and efficient asymmetric low-frequency pulsed strategy (ALPS) to significantly enhance the stability and the selectivity of the Cu-dimethylpyrazole complex Cu3(DMPz)3catalyst in CO2RR. Under traditional potentiostatic conditions, Cu3(DMPz)3exhibited poor CO2RR performance with the Faradaic efficiency (FE) of 34.5% for C2H4and FE of 5.9% for CH4as well as the low stability for less than 1 h. We optimized two distinguished ALPS methods toward CH4and C2H4, correspondingly. The high selectivities of catalytic product CH4(FECH4= 80.3% and above 76.6% within 24 h) and C2H4(FEC2H4= 70.7% and above 66.8% within 24 h) can be obtained, respectively. The ultralong stability for 300 h (FECH4> 60%) and 145 h (FEC2H4> 50%) was also recorded with the ALPS method. Microscopy (HRTEM, SAED, and HAADF) measurements revealed that the ALPS method in situgenerated and stabilized extremely dispersive and active Cu-based clusters (∼2.7 nm) from Cu3(DMPz)3. Meanwhile, ex situspectroscopies (XPS, AES, and XANES) and in situXANES indicated that this ALPS method modulated the Cu oxidation states, such as Cu(0 and I) with C2H4selectivity and Cu(I and II) with CH4selectivity. The mechanism under the ALPS methods was explored by in situATR-FTIR, in situRaman, and DFT computation. The ALPS methods provide a new opportunity to boost the selectivity and stability of CO2RR.