Steady state AC circuit
As we know that in steady state capacitor acts as OC and inductor acts as SC.


This is true only for DC analysis, where "steady state" refers to values of voltage and current that are not changing at all.


  But in steady state AC we deal with term like jXL or -jXC and uses phasor and other stuffs to determine circuit parameters like current and voltage. How it can happen when already all the values impedance values are either zero(in inductor) and infinite(in capacitor) ?


"Steady state" in AC analysis is a completely different concept. It means that the parameters of the excitation such as frequency and amplitude are not varying. It does NOT mean, however, that the instantaneous values of voltage and current are not changing, or that you can continue to model inductors and capacitors as shorts and opens. You need to evaluate their actual complex impedances at the excitation frequency. Those values are finite and nonzero, and they remain constant as long as the frequency doesn't change.