Abstract: The microstructure and micro-hardness of complete austenitization 46MnVS6 non-quenched and tempered steel were analyzed after cooling to room temperature at different cooling rates by using thermal dilatometer, optical microscope and Vickers hardness tester. The continuous cooling transformation (CCT) curves of supercooled austenite were tested. The influence of alloying element and cooling rate on the continuous cooling transformation of supercooled austenite was discussed. The results show that the CCT curve could be divided into high temperature transition region, middle temperature transition region and low termperature transition region, and the middle temperature transition region and low temperature transition region were separated. The microstructure was mainly ferrite and pearlite when the cooling rate was below 2℃·s^-1. With the increase of cooling rate, the content and average grain size of ferrite and pearlite decreased, and the content of martensite increased. The main microstructure was martensite when the cooling rate was over 5℃·s^-1. With the increase of cooling rate from 0.5℃·s^-1 to 60℃·s^-1, the micro-hardness of 46MnVS6 steel increased from 285 HV1 to 683 HV1.