Gas condensate consists essentionaly of two kinds of compounds: hydrocarbon compounds and nonhydrocarbon compounds such as (CO2, H2S, N2, H2O……..). Nonhydrocarbon compounds form a very small rate in gas condensate ,but it effect on many properties of gas condensate. This research studies the effect of these componentson the pseudocritical pressure and pseudocritical temperature of gas condensate which are very important to study the phase behavioure of gas condensate and to determine the region of retrograde phenomenas which happen in gas condensate reservoirs.The study was done by presenting some methods to calculate these properties and the correcting of these values if there are nonhydrocarbon components in the condensate . the calculations were made by Stewartt methode and we put a computed program to calculate the correcting pseudocritical properties and noncorrecting ones, then we compear the tow values by drawing many diagrams between the mole fraction of the component and the calculated pseudocritical temperature and pressure.