The main-belt comets (MBC) refer to both having the orbital characteristics of the main-belt asteroids and having the comet like coma or tail, its activity is driven by water ice sublimation. We collected MBC observation data from the past 20 years and plotted the Secular Light Curves (SLC) of the MBC 238P/Read, 259P/Garradd, 313P/Gibbs, 324P/La Sagra and 358P/PANSTARRS, thereby analyzing the activity characteristics of the MBCs. We get the following conclusions: (1) The activity of 238P was found to be relatively stable, while the activity of other main-belt comets showed varying degrees of attenuation compared to the previous perihelion passage. (2) By comparing the photometric age P_AGE, which reflects the activity of comets, we sorted the activity level of five main-belt comets and found that 324P had the strongest activity in 2010 and 313P had the weakest activity in 2014. (3) 313P showed significant non-perihelion activity during the 2020 perihelion passage, which was not observed in previous perihelion passages. (4) The time and heliocentric distance corresponding to the beginning and end of the main-belt comet's activity are asymmetric compared to the perihelion time and heliocentric distance.