Pleurotus eryngii has recently become the most commonly cultivated mushroom in East Asia. However, a long shelf life is required for export to distant regions. To obtain a long shelf life for mushrooms, different ratios of raw materials were mixed to develop new media based on crude protein and nitrogen free extract contents and thus 7 media designated A–G were prepared. Fruiting bodies from the “D” and “G” media containing 4.5 and 4.7% crude protein (with nitrogen free extract and crude protein ratios of 2.9 and 3.3), respectively, had the longest shelf life period (35.5 and 35.3 days) as a B grade, representing intact mushrooms with water and spores. Moreover, G medium showed significantly better mushrooms in yield (113.7 g/bottle), quality (7.3) and required days to harvest (15.4 days) compared to mushrooms produced in control medium (A), it was statistically proved by analysis of variance and Duncan’s multiple-range test (P < 0.05). The shelf life as a B grade was significantly extended with increased the crude protein (R2 = 0.774) and CaO contents (R2 = 0.608) in the media and regression analyses indicated that crude protein and CaO presented synergistic effects on shelf life (R2 = 0.728–0.819, P < 0.05). These results might be useful for mushroom farmers to produce more exportable mushrooms with a long shelf life.