The transient absorption properties of Rydberg atoms driven by two pulsed laser fields are investigated herein on the basis of the theory of density matrix equation, which describes the interaction of photon and material. It is found that owing to the weak coupling field, the probe absorption first increases to the maximum value and then decreases monotonically to zero with time. The maximum value of the probe absorption increases with an increase in Rabi frequency until the largest value is obtained. Then, it decreases gradually and the absorption with time presents the character of oscillation at the same time. When the coupling field's Rabi frequency is appropriate, the phenomenon of negative absorption occurs. The analysis of the evolution of population and the coherent term with time reveals that the coherent term caused by the influence of the coupling and probe field results in a negative absorption.