Abstract: Using NCEP/NCAR daily data in the period from 1994.5.6.00h to 5.23.12h. The short time scale evolution of the subtropical high for the western north Pacific basin is studied diagnostically. The diagnostic results are supported by the theoretic analyses and by a shallow-water equations model experiment. Results show that the interaction among a tropical cyclone in easterly current on the south of the subtropical high, its dispersion-deduced high value system, and the subtropical high can Great the subtropical flow pattern having asymmetric feature along the latitude circle and the ridge line with the direction from northeast to southwest rather than from right east to right west. The conditions under which the interaction nay occur are also disussed.