what parameter should be noticed in design sample and hold circuit?
As with any sample and hold, you need an opamp that introduces minimal errors from its input offset voltage, its input bias currents and its leakage impedance to ground. Most modern opamps specify these parameters.

You also need to ensure that your opamp is quick enough to slew its output to the input voltage in that time you allow between sampling and measuring.

If the sample capacitor is low i.e. a few pico farad then you need to take into account the added capacitance from the opamp input. You might also need to consider the opamp input noise voltage.

Finally, make sure your opamp can handle the signal range with the power rails you provide it.

Again, all these numbers are usually in the data sheet.