Cross sections measurement and search for exotic states at BESIII

With the data samples collected above DDbar open charm threshold at BESIII, Born cross sections of electron positron annihilation into various final states have been measured, in order to search exotic charmonium-like states. Some recent results will be reported in this presentation including the following processes: e+ e- -> D*s+ DsJ-, e+ e- -> gamma chi_c0/1/2, e+ e- -> pi+ pi- psi(2S), observation of psi(3770) -> Lambda anti-Lambda.