Co type and MnZ type at atomic and magnetic disorder are investigated for Co based Heusler alloy Co2MnZ (Z=Si, Ge, SN) as a function of quenching temperature. It is shown that Co type disorder preferentially proceeds with increase in quenching temperature while the MnGe type disorder preferentially proceeds in Co2MnGe. In Co2MnSn only the Mn-Sn type disorder proceeds. On the other hand decrease with in quenching temperature Co2MnGe, while it remains almost constant Co2MnSn.