The invention relates to the field of aloft work mechanical control and discloses a control system and method used for a telescopic cylinder and engineering machinery. The control system comprises a position sensor and a control device, wherein the position sensor is used for collecting the position of a piston rod of the telescopic cylinder, and the control device is used for executing the following operations: under the condition that the position of the piston rod reaches a first preset position, the telescopic cylinder is controlled to stop retracting; under the condition that the positionof the piston rod reaches a second preset position, the telescopic cylinder is controlled to stop stretching, wherein the first preset position is the initial position which doesn't reach the oil cylinder stroke and the distance of the initial position is the position of a first preset value; the second preset position is the stop position which doesn't reach the oil cylinder stroke and the distance of the stop position is the position of a second preset value. By the aid of the system, the two ends of the oil cylinder stroke can avoid producing the phenomena of hydraulic shock and unstable flow, accordingly, stable control of the telescopic cylinder is realized, and the phenomena of shaking and creeping of an arm support during the aloft work are reduced.