Allowed parameter regions for a tree-level inflation model

The early universe inflation is well known as a promising theory to explain the origin of large-scale structure of universe and to solve the early uni verse pressing problems. For a reasonable inflation model, the potential du ring inflation must be very flat, at least, in the direction of the inflati on. To construct the inflation potential all the known related astrophysics observations should be included. For a general tree-level hybrid inflation potential, which is not discussed fully so far, the parameters in it are s hown how to be constrained via the astrophysics data observed and to be obt ained to the expected accuracy, and to be consistent with cosmology require ments.