The invention discloses a telescopic control system and method for support oil cylinders and mechanical equipment. The telescopic control system comprises the multiple vertical support oil cylinders. The vertical support oil cylinders (1a) comprise the first vertical support oil cylinders and the second vertical support oil cylinders with the telescopic action start speed lower than that of the first vertical support oil cylinders. Rod end chambers of the vertical support oil cylinders (1a) are connected with first work oil ways (2) respectively, non-rod chambers of the vertical support oil cylinders (1a) are connected with second work oil ways (3) respectively, and the first work oil ways (2) and the second work oil ways (3) of the vertical support oil cylinders (1a) are connected to a shared hydraulic oil supply element through corresponding reversing control valves. At least the first work oil ways (2) of the first vertical support oil cylinders or the second work oil ways (3) are provided with flow control valves, and the hydraulic oil conveying resistance of the first vertical support oil cylinders is adjusted through flow control over the flow control valves.