Abstract: On the problem whether the van der Waals parameters a and b depend on temperature，different literature

gives different answer，and even the same literature in different pages gives contrary answer. In thermody

namics，they are approximately treated as constants due to matching the thermodynamic coordinates of the critical

point and van der Waals equation of state can be expressed as the corresponding state law. Once the parameters a

and b depend on the temperature，the corresponding state law does not hold true，and other peculiarities of the van

der Waals equation of state is lost accordingly. In statistical mechanics，we usually obtain a Virial expansion of the

equation of state; once the van der Waals equation is used to interpolate to this expansion，they are temperaturedependent

except some special cases. Therefore，the different statements on temperature dependence of the van der

Waals a and b parameter in thermodynamics and statistical mechanics are in fact originates from implicit assumption

of the same application domain of the van der Waals equation of state in two different disciplines.

Key words: van der Waals equation of state, law of corresponding states, second Virial coefficient