A thermal model estimating workpiece temperature in orthogonal turn-milling compound machining for the case with noneccentricity between rotation axes of workpiece and tool has been established in this paper. Milling tool and machining history were discretized into infinitesimal elements of equal size to deal with complicated cutter geometry and intermittent cutting procedure. The geometries of milling tool and workpiece were analyzed to calculate the instantaneous chip thickness, axial depth of cut, and angles of cutting entry and exit. Heat source during cutting process was considered as instantaneous moving rectangular heat source and heat conducting function in infinite solid thermal conductivity was developed. Experiments measuring cutting force and workpiece temperature were launched to test validity of this model and figure out the importance of effects those factors have on workpiece temperature from variance analysis of orthogonal experiment results. Furthermore, simulations to calculate peak temperature of workpiece were carried out by this model with relevant machining parameters and the results matched conclusions from experiment well.