In this work, we present nS1/2→(n+1)S1/2 two-photon excitation EIT-AT spectrum of Rydberg atom in the vapor cell. A ground state (6S1/2), a first excited state (6P3/2) and Rydberg state (69S1/2) of cesium atoms constitute a three-level system. A weak probe laser locking to the transition of 6S1/2(F=4)→6P3/2(F?=5) couples ground-state transition and the strong coupling laser drives Rydberg transition of 6P3/2→69S1/2 to yield electromagnetically induced transparency (EIT) effect, which realizes the optical detection of Rydberg atoms. Two Rydberg 69S1/2→70S1/2 levels are coupled with the microwave field at a frequency of f MW = 11.735 GHz, forming a microwave two-photon spectrum. To observe the influence of microwave electric field power on two-photon spectrum, we investigate the microwave coupled Rydberg EIT-AT spectrum at different microwave fields. The measurements shown that the EIT-AT splitting interval is proportional to the square of the microwave electric field at strong microwave field, and shows a nonlinear dependence at weak microwave electric field. The theoretical calculation is agreed with the experimental measurements. The work here play a significance for the precise measurement of microwave electric field.