Abstract: A definition on the dynamical characteristics in psychology is made. The authors put forward an effective metewand on psychological dynamical characteristics, obtained through the use of least squares on a number of randomly sampled people from China, with the test tool of UK. The metewand can reflect not only the dynamic characteristics in general, but can also conveniently give, according to the work curve of the subject, curves of evaluation of the subject under test. Finally the authors explain the evaluating process through an illustrative example. The process may be put into use in the automatic processing of UK.