When the electromagnetic ultrasonic transducer (EMAT) is applied to the castings and forgings with coarse grains for fast and online inspection, the signal-to-noise ratio ( SNR) and range resolution of the ultrasonic echoes are low due to the influence of harsh environments such as high temperature, large lift-off, and rough surface. To address the above problem, a finite element model for the testing process of a racetrack coil EMAT is formulated, which is based on the chirp signal excitation. The orthogonal test table is used to analyze the influence of EMAT design parameters, bandwidth and pulse width of the chirp signal on the peak and width of the main lobe width of the detected echo after pulse compression. In this way, the optimal combination of EMAT parameters referring to the peak and width of the main lobe are obtained, and they are evaluated by experiments. The detection capability of 0. 5 MHz tone burst signal as an excitation with different synchronization averages for Φ4 flat-bottomed hole is compared with that of chirp pulse compression with different lift-offs and no synchronization averages. Compared with the SNR of the tone burst excitation with 128 synchronization averages, results show that the SNR of the detected echo using the chirp pulse compression technology with no synchronous averaging from the Φ4 flat-bottomed hole is increased by 6. 6 dB. In addition, the SNR of the pulse compressed signal from the Φ4 flat-bottomed hole can reach 8. 0 dB with an EMAT′s lift-off of 3. 5 mm and no synchronization averages.