High-resolution strip maps of CS (J = 1-0) and H51-alpha line emission across the Orion bright bar are presented. The intensity of CS emission is weaker in the H II region with a rapid increase at the optical bar, while the H51-alpha line was detected only on the side of the H II region. The variation of the CS intensity can be reproduced by a beam-convolved step function with the position of the step coincident with the ionization front. The molecular cloud associated with the bright bar is redshifted relative to the ambient molecular cloud by about 2 km/s. This may suggest the dynamical interactions between the molecular cloud and the H II region excited by the Trapezium stars.