We report Lee-Yang zeros behavior at finite temperature and density. The quark number densities, 〈n〉, are calculated at the pure imaginary chemical potential iμqI, where no sign problem occurs. Then, the canonical partition functions, ZC(n,T,V), up to some maximal values of n are estimated through fitting theoretically motivated functions to 〈n〉, which are used to compute the Lee-Yang zeros. We study the temperature dependence of the distributions of the Lee-Yang zeros around the pseudo-critical temperature region T/Tc=0.84-1.35. In the distributions of the Lee-Yang zeros, we observe the Roberge-Weiss phase transition at T/Tc≥1.20. We discuss the dependence of the behaviors of Lee-Yang zeros on the maximal value of n, so that we can estimate a reliable infinite volume limit.