Abstract: The principal purpose of this invention is to enhance locking and unlocking mechanisms of a padlock by improving structural components which allow the locking core member to be pushed into the lock body in order to trigger the locking mechanism by forcing locking plate and semi-circular sector thereof to be firmly engaged with locking notch located at the end portions of the U-shaped shackle arms. The unlocking mechanism can be triggered by simply rotating the locking core member with a key in one direction for 90 degrees, causing the locking core member and locking semi-circular sector to be disengaged. Therefore, this invention provides a padlock with improved safety features as well as convenience of ease of use.