基于范德瓦尔斯方程推导了真实气体的临界特征、凝聚和过冷-相变过程. 分析结果表明：分子间较强的吸引作用及较弱的排斥作用使相变温度升高. 低于临界温度的过冷气体因压强阻力保持为亚稳态，需要外界诱导才能发生相变. 温度越低，压强阻力越小，且过冷气体与相变点的体积差越大. 温度下降的速度越快则过冷气体的相变也越快. 压强对气液共存线的影响与理想气体相差一个修正因子.

The critical characteristics, condensation and supercoolingphase transition processes of real gas are derived in terms of the van der Waals equation. The results of analysis indicate that the stronger attraction and the weaker repulsion between molecules correspond to the higher phase transition temperature. The supercooled gas, due to the pressure resistance, below the critical temperature is metastable, which requires an external induction to overcome the resistance to conduct phase transition. To reduce the temperature will decrease the resistance and increase the volume shrinkage from supercooling state to phase transition point. The faster the temperature drops, the faster the phase transition of the supercooled gas will be. The influence of pressure on the gasliquid coexistence line has a discrepancy of a correction factor from that in the ideal gas.