Using the matrix diagonalization method, we have studied two kinds of level
anti-crossing of Rydberg cesium atom in parallel electric and magnetic fie
lds. Our numerical results reveal that in the vicinity position of level cr
ossing between different parity states in a magnetic field, the energy leve
ls and other behaviors of the states are quite sensitive to the electric fi
eld. We tabulate some features which may be as a guide in experimental veri
fication.