Frequency Monitoring Network (FNET) has realized the synchronous measurement of system frequency in Sichuan-Chongqing Power Grid. Based on the FNET measured data of Sichuan-Chongqing Power Grid, this paper evaluates the frequency quality of the power grid in recent years. The frequency time-space distribution characteristic of Sichuan-Chongqing Power Grid is presented and the frequency disturbance recovery capacity is evaluated by using statistic method. With disturbance data from FNET, this paper determines the dominant modes of the system according to the TLS-ESPRIT identification method and observes the weak damping and low frequency oscillation phenomenon between Chengdu and Panzhihua under the 0.25 Hz mode. The conclusions contribute to understanding the frequency quality and dynamics of Sichuan-Chongqing Power Grid as well as improving the control scheme of system frequency.