This study investigates the phase behavior and fluid properties of a near-critical condensate gas reservoir located in the middeep Carboniferous formation of the Junggar Basin, China. Employing a combination of PVT techniques and empirical methods, including phase diagram analysis, liquid volume ratio assessment, and condensate content determination, we delineate the unique characteristics of this reservoir type. Experimental results reveal distinct phase phenomena, including (1) critical opalescence and fluid stratification, attributed to the significant density gradients near the critical region. (2) Comparative analysis with conventional condensate gas reservoirs underscores the atypical relationship between the dew point pressure and gas-oil ratio (GOR), crucial for reservoir management strategies. Furthermore, (3) empirical discrimination methods highlight the necessity of caution in classifying near-critical reservoirs, particularly concerning the presence of an oil rim. This research contributes novel insights into the understanding of near-critical condensate gas reservoirs, marking the discovery of the first such reservoir in the Junggar Basin.