In order to comprehensively investigate the discharge characteristics of an atmospheric-pressure radio-frequency (RF) pulsed discharge in Ar/CH4/CO2, a phase-resolved measurement is given in this paper. Firstly, the discharge characteristics of RF plasma in a gas mixture of Ar, CO2 and CH4 are investigated under different parameters. It is found peak power is more efficient than duty cycle in increasing the discharge area. Besides, a phase-resolved morphology of RF plasma is given. The discharge in the positive cycle is longer in length and stronger in emission intensity than in the negative cycle. Secondly, different activation paths of species have been obtained by using phase-resolved optical emission spectroscopy. Ar species is mainly activated by electron collision effect, while CH and C-2 are mainly activated by Ar metastable species. Finally, detailed electron kinetics is analyzed. The results show that most energy is transferred to the vibrational excitation compared to elastic activation, electronic excitation, and ionization under different ratios of CO2 and CH4 to Ar. Besides, under a higher ratio of CH4 and CO2 to Ar, the generating rate of species and power loss rate are higher. It proves that higher fraction of CO2 and CH4 is better for the conversion rate and energy efficiency under RF discharge in theory, which guides the reforming of CH4 and CO2 in RF discharge.