Abstract: Based on the presupernova WS15M⊙,the detailed calculations and comparisons of electron capture timescale and hydrodynamic timescale at one-dimension non-rotating and rotating case are done.The results show that the electron capture timescales are shorter than hydrodynamic timescales in a short time before shock bounce.This difference becomes more obvious at rotating case.The conclusions support a new supernova mechanism,and may make some new effects on the research of the explosion of supernova.