A sintered heat pipe, a manufacturing method thereof and a manufacturing method for a groove tube thereof are provided. The sintered heat pipe includes a groove tube, a sintered powder layer and a working fluid. The groove tube has a plurality of grooves and a first end and a second end opposite to the first end. Each groove extends along an axial direction of the groove tube. The first end and the second end are closed. The sintered powder layer is formed on an inside wall of the groove tube, and the groove tube is filled with the working fluid. The size of each powder in the sintered powder layer is greater than a width of each of the grooves.