A novel 3T2R hybrid mechanism that consists of a 3-RRP,4R,R parallel mechanism and a two degree of freedom rotating mechanism is proposed according to engineering application scene of labelling for the round steel end surfaces of a bundle. A method of combining two Monte Carlo methods is proposed to solve the workspace of the hybrid mechanism. The kinematics model of the hybrid mechanism is established. According to the geometric relationship of the parallel mechanism， the inverse solution equation is obtained，and the constraints of the workspace of the parallel mechanism are determined. The set of points in the workspace of the parallel mechanism is obtained by using Monte Carlo method. The kinematics positive solution of the series mechanism and the kinematics positive solution of the hybrid mechanism are obtained according to the coordinate transformation matrix. The coordinates of the points in the workspace of the parallel mechanism is substituted into the positive solution of the position of the hybrid mechanism， and by using Monte Carlo method， the set of points in the workspace of the hybrid mechanism is obtained.