A rack type telescopic handle of horticultural shears includes a fixed handle with a rack, a movable handle sheathed on the fixed handle, and a control device installed at an end of the movable handle, a movable gear pivotally coupled to the control device, and the control device controls an engagement and a separation of the movable gear with the rack, so that the movable handle can slide to an appropriate position on the fixed handle before the movable handle is fixed to the fixed handle so as to adjust the length of the handle of the horticultural shears.