This study evaluates the inelastic behavior and performance level of existing 31-stories buildings in Surabaya using the non-linear time history analysis (NLTHA). The evaluation was conducted because of some SNI 1726-2019 regulation changes. The selection of time history data adjusts to the characteristics of the Surabaya earthquake area through the response spectrum, magnitude, and slip mechanism. The predicted inelastic response from response spectrum analysis (RSA) will be compared to the actual inelastic response of non-linear time history analysis (NLTHA). The results of NLTHA show that the structure's performance level belongs to the life safety category (LS) category with a maximum drift ratio of 1.1%. Beam hinges exceed the maximum limit of immediate occupancy (IO) level. The maximum yielding moment ratio is 1.05. The maximum plastic rotation that occurs is 0.73%. Response reduction, inelastic deformation enlargement, and overstrength factors R, Cd, and Ω are 6.11, 4.74, and 1.82, respectively.