1. A nonvolatile memory device comprising: a memory cell array having a plurality of memory blocks; and a control logic circuit configured to store a parameter to access at least one of the plurality of memory blocks, configured to detect a variation of the parameter while accessing the at least one the memory block, and configured to store the varied parameter into the memory cell array in accordance with a result of the detection, wherein the control logic circuit is configured to utilize the varied parameter, which is stored in the memory cell array, while accessing the at least one memory block. wherein the control logic circuit is configured to detect a maximum value of a threshold voltage distribution of memory cells of the memory cell array, and configured to set a read voltage with reference to a result of the maximum value detected, and wherein the maximum value of the threshold voltage distribution corresponds to a same number of passed and failed memory cells of the memory cell array.