The invention relates to a milling and turning composite electric spindle assembly and numerical control machining equipment. The milling and turning composite electric spindle assembly comprises a spindle, a spindle shell and a spindle braking mechanism. The spindle braking mechanism comprises a rotary toothed disc, a positioning toothed disc and a movable toothed disc, the rotary toothed disc coaxially and fixedly sleeves the front end of the spindle, the positioning toothed disc coaxially sleeves the outer side of the rotary toothed disc and is provided with a rotating clearance, the positioning toothed disc is fixedly connected to the front end of the spindle shell, the movable toothed disc is mounted between the spindle shell and a front bearing flange in a sleeving mode and is slidably and hermetically matched with the spindle shell and the front bearing flange, an annular oil cavity is formed in the rear surface of the movable toothed disc, the structure and number of end teethof each toothed disc are the same, the end teeth of the rotary toothed disc and the positioning toothed disc are located on the rear end surface, and the end teeth of the movable toothed disc are located on the front end surface. The spindle braking mechanism is installed at the front end of the spindle and is close to a cutting point, the braking effect is good, the torque applied to the spindleis small during braking, so that the spindle meets the braking requirement without particularly large rigidity, and the deformation damage of the spindle caused by frequent braking can be effectivelyavoided.