how to select cylinder for scissor lift?

How much are you needing to lift?
How much space do you have in the scissor legs?
How is it going to be powered or operated?

Answering those questions should get you much closer to the cylinder that is going to be needed.

1t & 2t capacity
500X 1100 mm
hydraulically operated

Hey Akshay,
Glad you know the asnwers to the questions, have you tried reaching out to a supplier of hydraulic cylinders to see if they had any suggestions for your design? They have staff for this reason and they may be very helpful in this situation. Otherwise, I see they are resold through many suppliers, example below:

Website:
https://www.surpluscenter.com/Hydraulics/Hydraulic-Cylinders/Double-Acting-Hydraulic-Cylinders/

Maybe you could spec out your footprint that's available and see what models they offer that would fit and also meet your 1-2t, 500-1100mm needs.

Narrowed search for 2t, 1100mm:
https://www.surpluscenter.com/Hydraulics/Hydraulic-Cylinders/Double-Acting-Hydraulic-Cylinders/?page_no=1&fq=ATR_HydraulicCylinderStrokeRange:36\%22\+\-\+47.9\%22