Abstract: With the completion of medium-thick seam mining gradually,the proportion of thin seam mining will contin- ue to increase,and its safe and efficient mining is becoming increasingly important. Due to the limitation of mining space and harsh conditions,the shearer is prone to the problems of unreasonable structure design,instability and poor reliability. Taking new thin coal seam shearer of MG2∗100 / 455-BWD cutting parts as an investigation target,the rigid flexible coupling virtual prototype model of the shearer was established by Pro / E,ANSYS and ADAMS. The mechani- cal model of shearer spiral drum was established based on coal breaking theory. The problem of load addition of rigid-flexible coupling virtual prototype model was solved by programming with MATLAB. The maximum stress nodes’ time- domain information and Von Mises stress distribution of output shaft,shell and planetary carrier were obtained by virtu- al simulation. Based on the simulation results of 30 sets simulation models for different hauling speeds,the maximum stress distribution function of each key part was established. Based on the reliability theory of stress-strength interfer- ence,combined with the maximum stress distribution function of each key part and the strength distribution function of the material used,the reliability calculation model of each key part under multiple random loads was established con- sidering the cycle of loads. The reliabilities of output shaft,planet carrier and shell were cal-culated as 0. 978,0. 536 and 0. 614 respectively. The results show that the stress concentration phenomena exist on planetary carrier and shell. The maximum stress locates at the intersection of web and spline shaft of planetary carrier,and at the intersection of backside of idler shaft hole and outside of planetary reducer of the shell,respectively. After the improvement of the weak parts,the reliability of the planet carrier and shell are 0. 969 and 0. 9974 respectively,which can meet the opera- tion requirement. This method can effectively shorten the product design cycle and improve the design quality and reli- ability of the key parts of shearer.