In this paper, we study the magnetic activity properties for a sample of M-type stars in Kepler field by using the two light-curve-based magnetic proxies, i AC and R eff , which describe the periodicity and magnitude of light-curve variations, respectively. It is found that (1) stars with short rotational period might have a relatively large value of R eff (mean of R eff ) while stars with long period can’t have large R eff value; (2) there is a weak trend between the rotation period and the correlation of i AC and R eff , that is, the correlation of the two magnetic proxies tends to be positive for stars with shorter period and be zero and negative for stars with longer period; and finally (3) statistically speaking, the negative correlation stars can’t have a large value of R eff as positive correlation stars. We describe the similarities and differences of magnetic activities, base on current and previous analysis, for M- type and G-type stars. The similarity of magnetic activity behaviors between M-type stars and G-type stars implies that the two kinds of stars obey the same magnetic dynamo mechanism, though their internal structures of the convective zone may be distinctly different.
