We investigate the finite temperature QCD phase transition with three degenerate quark flavors using Mobius domain wall fermions. To explore the order of phase transition on the lower left corner of Columbia plot and if possible, to locate the critical endpoint

we performed simulations at temperatures around 181 and 121 MeV with lattice spacing $a=0.1361(20)$~fm corresponding to temporal lattice extent $N_{\tau}=8,12$ with varying quark mass for two different volumes with aspect ratios $N_{\sigma}/N_{\tau}$ ranging from 2 to 3. By analyzing the volume and mass dependence of the chiral condensate, disconnected chiral susceptibility and Binder cumulant we find that there is a crossover at $m_q^{\mathrm{\overline {MS}}}(2\, \mathrm{GeV}) \sim 44\, \mathrm{MeV}$ for $\mathrm{T_{pc}}\sim$ 181 MeV, At temperature 121 MeV, the binder cumulant suggests a crossover at $m_q^{\mathrm{\overline {MS}}}(2\, \mathrm{GeV}) \sim 3.7\, \mathrm{MeV}$,

although a study of volume dependence would be important to confirm this.